December: New Years Eve Outlook
12z Euro looks similar to the Canadian model with temperatures in the low to mid 30s across the area with more than enough moisture to work with next week...
-
wxman57
- Global Moderator
- Posts: 2621
- Joined: Thu Feb 04, 2010 5:34 am
- Location: Southwest Houston (Westbury)
- Contact:
I'm looking at a plot of 3-hrly temps and precip (12Z Euro) for next week. It has a low of 31 in central Houston next Tuesday with no precip that day. By Wednesday, it has a low in the upper 30s with precip starting between sunrise and noon and temps dropping to the mid 30s during the afternoon and staying in the mid to upper 30s Wednesday night. Another miserable cold rain event, it appears.
/\
Figures. Can't win in these here parts!
Figures. Can't win in these here parts!
Mike
Beaumont, TX
(IH-10 & College Street)
Beaumont, TX
(IH-10 & College Street)
-
vci_guy2003
- Posts: 224
- Joined: Mon Jun 28, 2010 4:04 am
- Contact:
That is interesting. I have a hunch that any precip mid next week will be frozen
Yeah I know it doesn't necessarily show frozen precip next week but it shows a favorable setup for wintry precip around these parts next week. Will temps be cold enough to support anything frozen? who knows this far out the finer details can be ironed out overtime.
-
srainhoutx
- Site Admin
- Posts: 19685
- Joined: Tue Feb 02, 2010 2:32 pm
- Location: Maggie Valley, NC
- Contact:
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SAN ANGELO TX
156 PM CST THU DEC 5 2013
TXZ049-054-064>066-071-072-098-099-113-114-127-128-052200-
FISHER-NOLAN-STERLING-COKE-RUNNELS-IRION-TOM GREEN-HASKELL-
THROCKMORTON-JONES-SHACKELFORD-TAYLOR-CALLAHAN-
INCLUDING THE CITIES OF...ROTAN...ROBY...SWEETWATER...
STERLING CITY...ROBERT LEE...BRONTE...BALLINGER...WINTERS...
MERTZON...SAN ANGELO...HASKELL...THROCKMORTON...WOODSON...
STAMFORD...ANSON...HAMLIN...ALBANY...ABILENE...CLYDE...BAIRD...
CROSS PLAINS
156 PM CST THU DEC 5 2013
..LIGHT FREEZING RAIN EXPANDING ACROSS THE CONCHO VALLEY AND
BIG COUNTRY...
AN AREA OF FREEZING RAIN AND SLEET WILL CONTINUE TO MOVE
NORTHEAST ACROSS THE CONCHO VALLEY AND BIG COUNTRY THROUGH 4 PM.
ALTHOUGH ANY ICE ACCUMULATIONS WILL BE LIGHT...A GLAZE OF ICE WILL
BE POSSIBLE ON ROADWAYS MAINLY ALONG AND WEST OF A SAN ANGELO TO
ABILENE LINE. THIS WILL INCLUDE THE INTERSTATE 20 CORRIDOR FROM
ABILENE TO SWEETWATER...WHERE SEVERAL ACCIDENTS HAVE ALREADY BEEN
REPORTED.
NATIONAL WEATHER SERVICE SAN ANGELO TX
156 PM CST THU DEC 5 2013
TXZ049-054-064>066-071-072-098-099-113-114-127-128-052200-
FISHER-NOLAN-STERLING-COKE-RUNNELS-IRION-TOM GREEN-HASKELL-
THROCKMORTON-JONES-SHACKELFORD-TAYLOR-CALLAHAN-
INCLUDING THE CITIES OF...ROTAN...ROBY...SWEETWATER...
STERLING CITY...ROBERT LEE...BRONTE...BALLINGER...WINTERS...
MERTZON...SAN ANGELO...HASKELL...THROCKMORTON...WOODSON...
STAMFORD...ANSON...HAMLIN...ALBANY...ABILENE...CLYDE...BAIRD...
CROSS PLAINS
156 PM CST THU DEC 5 2013
..LIGHT FREEZING RAIN EXPANDING ACROSS THE CONCHO VALLEY AND
BIG COUNTRY...
AN AREA OF FREEZING RAIN AND SLEET WILL CONTINUE TO MOVE
NORTHEAST ACROSS THE CONCHO VALLEY AND BIG COUNTRY THROUGH 4 PM.
ALTHOUGH ANY ICE ACCUMULATIONS WILL BE LIGHT...A GLAZE OF ICE WILL
BE POSSIBLE ON ROADWAYS MAINLY ALONG AND WEST OF A SAN ANGELO TO
ABILENE LINE. THIS WILL INCLUDE THE INTERSTATE 20 CORRIDOR FROM
ABILENE TO SWEETWATER...WHERE SEVERAL ACCIDENTS HAVE ALREADY BEEN
REPORTED.
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey
Member: National Weather Association
Facebook.com/Weather Infinity
Twitter @WeatherInfinity
Member: National Weather Association
Facebook.com/Weather Infinity
Twitter @WeatherInfinity
-
srainhoutx
- Site Admin
- Posts: 19685
- Joined: Tue Feb 02, 2010 2:32 pm
- Location: Maggie Valley, NC
- Contact:
AREA WEATHER UPDATE
NATIONAL WEATHER SERVICE FORT WORTH TX
206 PM CST THU DEC 5 2013
...WINTER WEATHER UPDATE FOR NORTH TEXAS...
THERE HAVE BEEN NO SIGNIFICANT CHANGES TO THE FORECAST FOR A MAJOR
WINTER STORM IMPACTING NORTH TEXAS FROM THIS AFTERNOON THROUGH
FRIDAY. WHILE THE FORECAST AND THE IMPACTS HAVE NOT CHANGED...
THIS DISCUSSION WILL ATTEMPT TO DESCRIBE HOW WE FEEL PRECIPITATION
TYPE AND ICE ACCUMULATION WILL EVOLVE DURING THIS EVENT.
FIRST OFF...WHAT WE ARE CONFIDENT IN:
A SOUTHWEST TO NORTHEAST ORIENTED BAND OF MODERATE TO AT TIMES
HEAVY PRECIPITATION WILL DEVELOP AND MOVE SLOWLY EAST ACROSS NORTH
AND CENTRAL TEXAS FROM THIS EVENING THROUGH THE OVERNIGHT HOURS.
THIS BAND OF PRECIPITATION WILL BE FAIRLY LARGE...AND IS EXPECTED
TO ENCOMPASS THE AREA HIGHLIGHTED IN A WINTER STORM WARNING.
SUB-FREEZING TEMPERATURES WILL BUILD ACROSS NORTH TEXAS FROM
NORTHWEST TO SOUTHEAST BEGINNING AROUND SUNSET TONIGHT THROUGH
SUNRISE FRIDAY MORNING. AT THE TIME OF THIS DISCUSSION THE
FREEZING LINE WAS LOCATED ALONG A LINE FROM SHERMAN TO DENTON TO
HASLET TO MINERAL WELLS AND THEN CONTINUING SOUTHWEST TO
BROWNWOOD. THIS LINE IS NOT EXPECTED TO MOVE MUCH DURING THE
DAYLIGHT HOURS OF THE DAY...OR THROUGH 6 PM OR SO.
THE LIGHT BAND OF PRECIPITATION DEVELOPING ALONG A BRECKENRIDGE TO
GAINESVILLE LINE AT THE TIME OF THIS DISCUSSION (130 PM) IS NOT
EVEN ASSOCIATED WITH THE MAIN CORE OF PRECIPITATION MENTIONED
ABOVE. THIS LIGHTER BAND OF PRECIPITATION WILL BE MONITORED
CLOSELY THROUGH THIS EVENING FOR ANY MOVEMENT AS IT COULD CAUSE
TEMPERATURES TO FALL BELOW FREEZING FASTER THAN EXPECTED THIS
EVENING.
WITHIN THE BAND OF PRECIPITATION THAT WE ARE EXPECTING TO DEVELOP
ACROSS NORTH TEXAS THIS EVENING AND OVERNIGHT...ONE QUARTER TO ONE
HALF INCH OF PRECIPITATION IS VERY LIKELY. CONFIDENCE IS HIGH THAT
THE BULK OF THIS PRECIPITATION WILL FALL WITH TEMPERATURES BELOW
FREEZING RESULTING IN POTENTIAL ICE ACCUMULATIONS OF ONE QUARTER
TO ONE HALF INCH ACROSS MOST OF THE WINTER STORM WARNING AREA.
THAT SAID...THERE ARE SOME CAVEATS THAT WILL BE DISCUSSED BELOW IN
TERMS OF ACTUAL ICE ACCUMULATION ON SURFACES.
...HOW ICE ACCUMULATION WORKS AND WILL VARY ACROSS NORTH TEXAS
DURING THIS EVENT...
FREEZING RAIN OCCURS WHEN PRECIPITATION FALLS FROM THE CLOUDS IN A
LIQUID FORM...BUT THE TEMPERATURES NEAR AND AT THE SURFACE ARE
BELOW FREEZING. SO WE ACTUALLY HAVE JUST PLAIN OLD LIQUID RAIN
FALLING FROM THE SKIES...BUT WHEN TEMPERATURES AT THE SURFACE ARE
BELOW FREEZING THE RAIN CAN POTENTIALLY FREEZE UPON CONTACT WITH
THE GROUND...OR WHATEVER THE RAIN FALLS ON (I.E. TREES...POWER
LINES... ETC). THE WORD "POTENTIALLY" IS USED HERE BECAUSE WHETHER
THE RAIN FREEZES UPON CONTACT WITH SOMETHING IS DEPENDENT UPON TWO
FACTORS:
1. THE TEMPERATURE OF THE RAIN ITSELF THAT IS FALLING.
2. THE TEMPERATURE OF THE ACTUAL THING THAT THE RAIN IS FALLING
ON.
DURING THIS EVENT...THE RAIN THAT FALLS WILL DO SO THROUGH A LAYER
OF SUB-FREEZING AIR THAT RANGES FROM A FEW HUNDRED FEET THICK
SOUTHEAST OF WACO...TO ABOUT 5000 FEET THICK UP AROUND GRAHAM AND
BOWIE. WHERE THE WINTER STORM WARNING IS IN EFFECT...THE LAYER OF
SUB-FREEZING AIR IS EXPECTED TO BE DEEP ENOUGH FOR RAIN TO REACH
THE GROUND AT A TEMPERATURE OF RIGHT AROUND 32 DEG F. FURTHER
SOUTHEAST THE RAIN WILL BE WARMER THAN 32 DEGREES AND IN GENERAL
HAS LESS OF A CHANCE OF FREEZING UPON REACHING THE GROUND AS A
RESULT.
IN THE WINTER STORM WARNING AREA...WE ARE HIGHLY CONFIDENT THAT
RAIN WILL BE RIGHT AROUND FREEZING BEFORE IT REACHES THE
GROUND...SO WITH REGARDS TO THAT PROBLEM...RAIN SHOULD BE COLD
ENOUGH TO FREEZE ON CONTACT. THE SECOND POINT THOUGH IS
IMPORTANT...SOIL TEMPERATURES ACROSS NORTH TEXAS ARE HOLDING IN
THE MID 40S NEAR THE RED RIVER TO THE MID 50S ACROSS THE DFW
METROPLEX.
THIS MEANS THAT THERE IS NO CHANCE FOR RAIN TO FREEZE
ON SURFACES IN CONTACT WITH THE GROUND IMMEDIATELY AFTER IT STARTS
TO RAIN. WE WILL HAVE TO SEE NOT ONLY SURFACE TEMPERATURES BELOW
FREEZING...BUT RAIN WITH SURFACE TEMPERATURES BELOW FREEZING FOR
AT LEAST 2-3 HOURS BEFORE ICE IS LIKELY TO ACCUMULATE ON SURFACES
IN CONTACT WITH THE GROUND. WITH THIS IN MIND...THERE IS A VERY
IMPORTANT POINT TO MAKE:
HOW MUCH RAIN FALLS WHILE TEMPERATURES ARE BELOW FREEZING IS NOT
EQUAL TO ICE ACCUMULATION ON ROADWAYS.
DETERMINING HOW MUCH OF THE RAIN THAT FALLS WITH TEMPERATURES
BELOW FREEZING ACTUALLY ACCUMULATES AS ICE ON THE ROADWAYS IS
EXTREMELY COMPLICATED...BUT HERE IS SOME GENERAL GUIDANCE WE WILL
WATCH FOR:
1. IF RAIN IS FALLING AND THE SURFACE TEMPERATURE IS 28 DEGREES OR
BELOW...A LARGE PORTION OF THE FALLING RAIN WILL BECOME ICE UPON
CONTACT WITH THE GROUND. WE MAY ONLY NEED 1 TO AT MOST 2 HOURS OF
RAIN BEFORE SIGNIFICANT ICE ACCUMULATIONS BEGIN ON MAIN ROADWAYS.
2. FOR RAIN FALLING WITH SURFACE TEMPERATURES OF 29 TO 31
DEGREES...WE WILL NEED TO SEE RAINFALL FOR ABOUT 3 HOURS BEFORE
ICE STARTS TO ACCUMULATE ON ROAD SURFACES.
3. FOR RAIN FALLING WITH SURFACE TEMPERATURES RIGHT AT 32
DEGREES...IT MAY TAKE SEVERAL HOURS TO GET THE GROUND COOL ENOUGH
TO START TO ACCUMULATE ICE.
KEEPING THE ABOVE POINTS IN MIND...AND THE FACT THAT WE EXPECT
TEMPERATURES TO FALL BELOW FREEZING FROM NORTHWEST TO
SOUTHEAST...WE EXPECT THE LARGEST ICE ACCUMULATIONS AND IMPACTS TO
MAIN ROADWAYS FOR NORTHERN AND NORTHWESTERN PORTIONS OF THE WINTER
STORM WARNING AREA WHERE ICE ACCUMULATIONS ONE HALF INCH ARE MOST
LIKELY.
FURTHER SOUTHEAST...WE STILL EXPECT ONE QUARTER TO ONE HALF INCH
OF PRECIPITATION TO OCCUR...BUT AS MENTIONED ABOVE...A PORTION OF
THIS PRECIPITATION WILL BE SPENT COOLING DOWN GROUND TEMPERATURES
AND THEREFORE WILL NOT CONTRIBUTE DIRECTLY TO ICE ON ROADWAYS. FOR
THESE LOCATIONS...ONE QUARTER OF AN INCH OF ICE IS LIKELY TO
ACCUMULATE ON AREA ROADWAYS.
EITHER WAY...ONE QUARTER TO ONE HALF OF AN INCH OF ICE ON AREA
ROADWAYS IS GOING TO HAVE A VERY NEGATIVE IMPACT ON THE MORNING
COMMUTE FOR FRIDAY FOR ALL LOCATIONS INCLUDED IN WINTER STORM
WARNINGS DURING THIS EVENT. POWER LINES WILL GENERALLY ACCUMULATE
MORE ICE THAN AREA ROADWAYS...SO ANTICIPATE POWER OUTAGES ACROSS
THE AREA DURING THIS EVENT. WE WILL BE CLOSELY WATCHING THE
PROGRESS OF THE 28/29 DEGREE AIR DURING THIS EVENT AS THIS WILL
LARGELY DICTATE HOW QUICKLY ICE ACCUMULATES ON MAIN ROADWAYS.
ONE IMPORTANT NOTE...EVERYTHING DISCUSSED ABOVE ONLY APPLIES TO
ROAD SURFACES IN CONTACT WITH THE GROUND. BRIDGES... OVERPASSES
AND ANY ELEVATED SURFACE THAT ALLOWS FOR AIRFLOW ALL AROUND THE
SURFACE WILL HAVE A TEMPERATURE VERY CLOSE TO THE AIR TEMPERATURE
AND THEREFORE WILL ACCUMULATE ICE MUCH FASTER AND IN MUCH HIGHER
QUANTITIES.
LAST NOTE...WHICH IS FAIRLY IMPORTANT...WITHIN THE BROAD SWATH OF
PRECIPITATION/FREEZING RAIN DURING THIS EVENT...NEARLY ALL MODEL
GUIDANCE INDICATES A NARROW BAND OF ENHANCED PRECIPITATION
CONTAINING ISOLATED THUNDERSTORMS. NEEDLESS TO SAY...ELEVATED
THUNDERSTORMS WITH TEMPERATURES BELOW FREEZING WILL LIKELY HAVE
NEGATIVE CONSEQUENCES FOR THOSE IMPACTED. THIS NARROW BAND OF
ENHANCED PRECIPITATION IS EXPECTED TO BE ONLY ABOUT 20 TO 30 MILES
WIDE...MAKING ITS FORECAST POSITION VERY DIFFICULT TO PIN DOWN.
WHEREVER IT IT SETS UP...PRECIPITATION AMOUNTS WILL INCREASE FROM
AROUND ONE HALF INCH TO AROUND 1.0 INCH...OR AROUND DOUBLE
SURROUNDING AREAS.
12Z MODEL GUIDANCE INDICATES THE FOLLOWING:
THE GFS AND NAM HAVE THIS ENHANCED BAND OF PRECIPITATION EXISTING
FROM THE DALLAS/TARRANT COUNTY BORDER NORTHEAST TOWARDS PARIS.
THE ECMWF AND RAP INDICATE THIS BAND WILL EXIST TO THE SOUTHEAST
OF THE METROPLEX...EXTENDING FROM HILLSBORO NORTHEAST TOWARDS
SULPHUR SPRINGS.
EITHER WAY...THERE VERY LIKELY WILL BE AN ENHANCED ZONE OF
PRECIPITATION DURING THIS EVENT...AND THOSE AREAS ARE MUCH MORE
LIKELY TO SEE POWER OUTAGES AS ICE ACCUMULATIONS IN EXCESS OF ONE
HALF INCH ARE PROBABLE. WE WILL BE WATCHING FOR SOME BETTER
CONSISTENCY WITH REGARDS TO THE PLACEMENT OF THIS LINE THROUGH
THIS EVENING.
IF YOU ARE IN A WINTER STORM WARNING...IT IS BEST TO PREPARE TO BE
ABLE TO STAY AT YOUR RESIDENCE FOR AT LEAST 48 HOURS REGARDLESS OF
THE OUTCOME OF THIS EVENT. HAVING THE ABILITY TO RIDE OUT A 48
HOUR PERIOD WITHOUT BEING ABLE TO TRAVEL AND POSSIBLY WITHOUT
POWER IS CERTAINLY A WORST CASE SCENARIO...BUT THERE IS LITTLE
HARM IN PREPARING IN CASE THE WORST CASE SCENARIO PANS OUT. MOST
LIKELY IMPACTS WILL NOT BE SEVERE ENOUGH TO RESULT IN 48 HOURS OF
IMPOSSIBLE TRAVEL AND WITHOUT POWER FOR MOST OF THE AREA.
CAVANAUGH
NOTE: THIS IS AN EXPERIMENTAL PRODUCT MEANT TO INCREASE
INFORMATION
EXCHANGE ON THE MESOSCALE AND STORM SCALE...MAINLY DURING WARNING
OPERATIONS. THIS PRODUCT MAY NOT BE ISSUED DURING EVERY WARNING
EVENT.
TERMS DEFINED:
3BS = THREE-BODY SCATTER (REFLECTIVITY FLARE SIGNATURE FROM HAIL)
AP = ANOMALOUS PROPAGATION
BWER = BOUNDED WEAK ECHO REGION
CAPE = CONVECTIVE AVAILABLE POTENTIAL ENERGY (INSTABILITY)
CIN = CONVECTIVE INHIBITION (RELATED TO CAP STRENGTH)
CWA = COUNTY WARNING AREA
GIANT HAIL = HAIL 2 INCHES IN DIAMETER OR LARGER
HP = HIGH-PRECIPITATION SUPERCELL
LP = LOW-PRECIPITATION SUPERCELL
MCS = MESOSCALE CONVECTIVE SYSTEM (ORGANIZED THUNDERSTORM SYSTEM)
MESO = MESOCYCLONE
MT = MAX STORM TOP
POSH = PROBABILITY OF SEVERE HAIL ALGORITHM
RDA = WSR-88D RADAR SITE
RFD = REAR FLANK DOWNDRAFT
SCIT = STORM CELL IDENTIFICATION AND TRACKING ALGORITHM
SREH = STORM-RELATIVE ENVIRONMENTAL HELICITY
SRM = STORM-RELATIVE RADIAL VELOCITY
TDA = ALGORITHM TO DETECT STRONG CYCLONIC SHEAR
TVS = TORNADIC VORTEX SIGNATURE
V = GROUND-RELATIVE RADIAL VELOCITY
VCP = VOLUME COVERAGE PATTERN OF WSR-88D
VIL = VERTICALLY INTEGRATED LIQUID
VOL-Z = REFLECTIVITY AT LOW...MID...AND HIGH LEVELS
Z = REFLECTIVITY
NATIONAL WEATHER SERVICE FORT WORTH TX
206 PM CST THU DEC 5 2013
...WINTER WEATHER UPDATE FOR NORTH TEXAS...
THERE HAVE BEEN NO SIGNIFICANT CHANGES TO THE FORECAST FOR A MAJOR
WINTER STORM IMPACTING NORTH TEXAS FROM THIS AFTERNOON THROUGH
FRIDAY. WHILE THE FORECAST AND THE IMPACTS HAVE NOT CHANGED...
THIS DISCUSSION WILL ATTEMPT TO DESCRIBE HOW WE FEEL PRECIPITATION
TYPE AND ICE ACCUMULATION WILL EVOLVE DURING THIS EVENT.
FIRST OFF...WHAT WE ARE CONFIDENT IN:
A SOUTHWEST TO NORTHEAST ORIENTED BAND OF MODERATE TO AT TIMES
HEAVY PRECIPITATION WILL DEVELOP AND MOVE SLOWLY EAST ACROSS NORTH
AND CENTRAL TEXAS FROM THIS EVENING THROUGH THE OVERNIGHT HOURS.
THIS BAND OF PRECIPITATION WILL BE FAIRLY LARGE...AND IS EXPECTED
TO ENCOMPASS THE AREA HIGHLIGHTED IN A WINTER STORM WARNING.
SUB-FREEZING TEMPERATURES WILL BUILD ACROSS NORTH TEXAS FROM
NORTHWEST TO SOUTHEAST BEGINNING AROUND SUNSET TONIGHT THROUGH
SUNRISE FRIDAY MORNING. AT THE TIME OF THIS DISCUSSION THE
FREEZING LINE WAS LOCATED ALONG A LINE FROM SHERMAN TO DENTON TO
HASLET TO MINERAL WELLS AND THEN CONTINUING SOUTHWEST TO
BROWNWOOD. THIS LINE IS NOT EXPECTED TO MOVE MUCH DURING THE
DAYLIGHT HOURS OF THE DAY...OR THROUGH 6 PM OR SO.
THE LIGHT BAND OF PRECIPITATION DEVELOPING ALONG A BRECKENRIDGE TO
GAINESVILLE LINE AT THE TIME OF THIS DISCUSSION (130 PM) IS NOT
EVEN ASSOCIATED WITH THE MAIN CORE OF PRECIPITATION MENTIONED
ABOVE. THIS LIGHTER BAND OF PRECIPITATION WILL BE MONITORED
CLOSELY THROUGH THIS EVENING FOR ANY MOVEMENT AS IT COULD CAUSE
TEMPERATURES TO FALL BELOW FREEZING FASTER THAN EXPECTED THIS
EVENING.
WITHIN THE BAND OF PRECIPITATION THAT WE ARE EXPECTING TO DEVELOP
ACROSS NORTH TEXAS THIS EVENING AND OVERNIGHT...ONE QUARTER TO ONE
HALF INCH OF PRECIPITATION IS VERY LIKELY. CONFIDENCE IS HIGH THAT
THE BULK OF THIS PRECIPITATION WILL FALL WITH TEMPERATURES BELOW
FREEZING RESULTING IN POTENTIAL ICE ACCUMULATIONS OF ONE QUARTER
TO ONE HALF INCH ACROSS MOST OF THE WINTER STORM WARNING AREA.
THAT SAID...THERE ARE SOME CAVEATS THAT WILL BE DISCUSSED BELOW IN
TERMS OF ACTUAL ICE ACCUMULATION ON SURFACES.
...HOW ICE ACCUMULATION WORKS AND WILL VARY ACROSS NORTH TEXAS
DURING THIS EVENT...
FREEZING RAIN OCCURS WHEN PRECIPITATION FALLS FROM THE CLOUDS IN A
LIQUID FORM...BUT THE TEMPERATURES NEAR AND AT THE SURFACE ARE
BELOW FREEZING. SO WE ACTUALLY HAVE JUST PLAIN OLD LIQUID RAIN
FALLING FROM THE SKIES...BUT WHEN TEMPERATURES AT THE SURFACE ARE
BELOW FREEZING THE RAIN CAN POTENTIALLY FREEZE UPON CONTACT WITH
THE GROUND...OR WHATEVER THE RAIN FALLS ON (I.E. TREES...POWER
LINES... ETC). THE WORD "POTENTIALLY" IS USED HERE BECAUSE WHETHER
THE RAIN FREEZES UPON CONTACT WITH SOMETHING IS DEPENDENT UPON TWO
FACTORS:
1. THE TEMPERATURE OF THE RAIN ITSELF THAT IS FALLING.
2. THE TEMPERATURE OF THE ACTUAL THING THAT THE RAIN IS FALLING
ON.
DURING THIS EVENT...THE RAIN THAT FALLS WILL DO SO THROUGH A LAYER
OF SUB-FREEZING AIR THAT RANGES FROM A FEW HUNDRED FEET THICK
SOUTHEAST OF WACO...TO ABOUT 5000 FEET THICK UP AROUND GRAHAM AND
BOWIE. WHERE THE WINTER STORM WARNING IS IN EFFECT...THE LAYER OF
SUB-FREEZING AIR IS EXPECTED TO BE DEEP ENOUGH FOR RAIN TO REACH
THE GROUND AT A TEMPERATURE OF RIGHT AROUND 32 DEG F. FURTHER
SOUTHEAST THE RAIN WILL BE WARMER THAN 32 DEGREES AND IN GENERAL
HAS LESS OF A CHANCE OF FREEZING UPON REACHING THE GROUND AS A
RESULT.
IN THE WINTER STORM WARNING AREA...WE ARE HIGHLY CONFIDENT THAT
RAIN WILL BE RIGHT AROUND FREEZING BEFORE IT REACHES THE
GROUND...SO WITH REGARDS TO THAT PROBLEM...RAIN SHOULD BE COLD
ENOUGH TO FREEZE ON CONTACT. THE SECOND POINT THOUGH IS
IMPORTANT...SOIL TEMPERATURES ACROSS NORTH TEXAS ARE HOLDING IN
THE MID 40S NEAR THE RED RIVER TO THE MID 50S ACROSS THE DFW
METROPLEX.
THIS MEANS THAT THERE IS NO CHANCE FOR RAIN TO FREEZE
ON SURFACES IN CONTACT WITH THE GROUND IMMEDIATELY AFTER IT STARTS
TO RAIN. WE WILL HAVE TO SEE NOT ONLY SURFACE TEMPERATURES BELOW
FREEZING...BUT RAIN WITH SURFACE TEMPERATURES BELOW FREEZING FOR
AT LEAST 2-3 HOURS BEFORE ICE IS LIKELY TO ACCUMULATE ON SURFACES
IN CONTACT WITH THE GROUND. WITH THIS IN MIND...THERE IS A VERY
IMPORTANT POINT TO MAKE:
HOW MUCH RAIN FALLS WHILE TEMPERATURES ARE BELOW FREEZING IS NOT
EQUAL TO ICE ACCUMULATION ON ROADWAYS.
DETERMINING HOW MUCH OF THE RAIN THAT FALLS WITH TEMPERATURES
BELOW FREEZING ACTUALLY ACCUMULATES AS ICE ON THE ROADWAYS IS
EXTREMELY COMPLICATED...BUT HERE IS SOME GENERAL GUIDANCE WE WILL
WATCH FOR:
1. IF RAIN IS FALLING AND THE SURFACE TEMPERATURE IS 28 DEGREES OR
BELOW...A LARGE PORTION OF THE FALLING RAIN WILL BECOME ICE UPON
CONTACT WITH THE GROUND. WE MAY ONLY NEED 1 TO AT MOST 2 HOURS OF
RAIN BEFORE SIGNIFICANT ICE ACCUMULATIONS BEGIN ON MAIN ROADWAYS.
2. FOR RAIN FALLING WITH SURFACE TEMPERATURES OF 29 TO 31
DEGREES...WE WILL NEED TO SEE RAINFALL FOR ABOUT 3 HOURS BEFORE
ICE STARTS TO ACCUMULATE ON ROAD SURFACES.
3. FOR RAIN FALLING WITH SURFACE TEMPERATURES RIGHT AT 32
DEGREES...IT MAY TAKE SEVERAL HOURS TO GET THE GROUND COOL ENOUGH
TO START TO ACCUMULATE ICE.
KEEPING THE ABOVE POINTS IN MIND...AND THE FACT THAT WE EXPECT
TEMPERATURES TO FALL BELOW FREEZING FROM NORTHWEST TO
SOUTHEAST...WE EXPECT THE LARGEST ICE ACCUMULATIONS AND IMPACTS TO
MAIN ROADWAYS FOR NORTHERN AND NORTHWESTERN PORTIONS OF THE WINTER
STORM WARNING AREA WHERE ICE ACCUMULATIONS ONE HALF INCH ARE MOST
LIKELY.
FURTHER SOUTHEAST...WE STILL EXPECT ONE QUARTER TO ONE HALF INCH
OF PRECIPITATION TO OCCUR...BUT AS MENTIONED ABOVE...A PORTION OF
THIS PRECIPITATION WILL BE SPENT COOLING DOWN GROUND TEMPERATURES
AND THEREFORE WILL NOT CONTRIBUTE DIRECTLY TO ICE ON ROADWAYS. FOR
THESE LOCATIONS...ONE QUARTER OF AN INCH OF ICE IS LIKELY TO
ACCUMULATE ON AREA ROADWAYS.
EITHER WAY...ONE QUARTER TO ONE HALF OF AN INCH OF ICE ON AREA
ROADWAYS IS GOING TO HAVE A VERY NEGATIVE IMPACT ON THE MORNING
COMMUTE FOR FRIDAY FOR ALL LOCATIONS INCLUDED IN WINTER STORM
WARNINGS DURING THIS EVENT. POWER LINES WILL GENERALLY ACCUMULATE
MORE ICE THAN AREA ROADWAYS...SO ANTICIPATE POWER OUTAGES ACROSS
THE AREA DURING THIS EVENT. WE WILL BE CLOSELY WATCHING THE
PROGRESS OF THE 28/29 DEGREE AIR DURING THIS EVENT AS THIS WILL
LARGELY DICTATE HOW QUICKLY ICE ACCUMULATES ON MAIN ROADWAYS.
ONE IMPORTANT NOTE...EVERYTHING DISCUSSED ABOVE ONLY APPLIES TO
ROAD SURFACES IN CONTACT WITH THE GROUND. BRIDGES... OVERPASSES
AND ANY ELEVATED SURFACE THAT ALLOWS FOR AIRFLOW ALL AROUND THE
SURFACE WILL HAVE A TEMPERATURE VERY CLOSE TO THE AIR TEMPERATURE
AND THEREFORE WILL ACCUMULATE ICE MUCH FASTER AND IN MUCH HIGHER
QUANTITIES.
LAST NOTE...WHICH IS FAIRLY IMPORTANT...WITHIN THE BROAD SWATH OF
PRECIPITATION/FREEZING RAIN DURING THIS EVENT...NEARLY ALL MODEL
GUIDANCE INDICATES A NARROW BAND OF ENHANCED PRECIPITATION
CONTAINING ISOLATED THUNDERSTORMS. NEEDLESS TO SAY...ELEVATED
THUNDERSTORMS WITH TEMPERATURES BELOW FREEZING WILL LIKELY HAVE
NEGATIVE CONSEQUENCES FOR THOSE IMPACTED. THIS NARROW BAND OF
ENHANCED PRECIPITATION IS EXPECTED TO BE ONLY ABOUT 20 TO 30 MILES
WIDE...MAKING ITS FORECAST POSITION VERY DIFFICULT TO PIN DOWN.
WHEREVER IT IT SETS UP...PRECIPITATION AMOUNTS WILL INCREASE FROM
AROUND ONE HALF INCH TO AROUND 1.0 INCH...OR AROUND DOUBLE
SURROUNDING AREAS.
12Z MODEL GUIDANCE INDICATES THE FOLLOWING:
THE GFS AND NAM HAVE THIS ENHANCED BAND OF PRECIPITATION EXISTING
FROM THE DALLAS/TARRANT COUNTY BORDER NORTHEAST TOWARDS PARIS.
THE ECMWF AND RAP INDICATE THIS BAND WILL EXIST TO THE SOUTHEAST
OF THE METROPLEX...EXTENDING FROM HILLSBORO NORTHEAST TOWARDS
SULPHUR SPRINGS.
EITHER WAY...THERE VERY LIKELY WILL BE AN ENHANCED ZONE OF
PRECIPITATION DURING THIS EVENT...AND THOSE AREAS ARE MUCH MORE
LIKELY TO SEE POWER OUTAGES AS ICE ACCUMULATIONS IN EXCESS OF ONE
HALF INCH ARE PROBABLE. WE WILL BE WATCHING FOR SOME BETTER
CONSISTENCY WITH REGARDS TO THE PLACEMENT OF THIS LINE THROUGH
THIS EVENING.
IF YOU ARE IN A WINTER STORM WARNING...IT IS BEST TO PREPARE TO BE
ABLE TO STAY AT YOUR RESIDENCE FOR AT LEAST 48 HOURS REGARDLESS OF
THE OUTCOME OF THIS EVENT. HAVING THE ABILITY TO RIDE OUT A 48
HOUR PERIOD WITHOUT BEING ABLE TO TRAVEL AND POSSIBLY WITHOUT
POWER IS CERTAINLY A WORST CASE SCENARIO...BUT THERE IS LITTLE
HARM IN PREPARING IN CASE THE WORST CASE SCENARIO PANS OUT. MOST
LIKELY IMPACTS WILL NOT BE SEVERE ENOUGH TO RESULT IN 48 HOURS OF
IMPOSSIBLE TRAVEL AND WITHOUT POWER FOR MOST OF THE AREA.
CAVANAUGH
NOTE: THIS IS AN EXPERIMENTAL PRODUCT MEANT TO INCREASE
INFORMATION
EXCHANGE ON THE MESOSCALE AND STORM SCALE...MAINLY DURING WARNING
OPERATIONS. THIS PRODUCT MAY NOT BE ISSUED DURING EVERY WARNING
EVENT.
TERMS DEFINED:
3BS = THREE-BODY SCATTER (REFLECTIVITY FLARE SIGNATURE FROM HAIL)
AP = ANOMALOUS PROPAGATION
BWER = BOUNDED WEAK ECHO REGION
CAPE = CONVECTIVE AVAILABLE POTENTIAL ENERGY (INSTABILITY)
CIN = CONVECTIVE INHIBITION (RELATED TO CAP STRENGTH)
CWA = COUNTY WARNING AREA
GIANT HAIL = HAIL 2 INCHES IN DIAMETER OR LARGER
HP = HIGH-PRECIPITATION SUPERCELL
LP = LOW-PRECIPITATION SUPERCELL
MCS = MESOSCALE CONVECTIVE SYSTEM (ORGANIZED THUNDERSTORM SYSTEM)
MESO = MESOCYCLONE
MT = MAX STORM TOP
POSH = PROBABILITY OF SEVERE HAIL ALGORITHM
RDA = WSR-88D RADAR SITE
RFD = REAR FLANK DOWNDRAFT
SCIT = STORM CELL IDENTIFICATION AND TRACKING ALGORITHM
SREH = STORM-RELATIVE ENVIRONMENTAL HELICITY
SRM = STORM-RELATIVE RADIAL VELOCITY
TDA = ALGORITHM TO DETECT STRONG CYCLONIC SHEAR
TVS = TORNADIC VORTEX SIGNATURE
V = GROUND-RELATIVE RADIAL VELOCITY
VCP = VOLUME COVERAGE PATTERN OF WSR-88D
VIL = VERTICALLY INTEGRATED LIQUID
VOL-Z = REFLECTIVITY AT LOW...MID...AND HIGH LEVELS
Z = REFLECTIVITY
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey
Member: National Weather Association
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Awful weather up here in OKC/Norman. Very heavy sleet and ice is building up on campus. They have closed OU for rest of the day, no word yet for tomorrow, though I expect that to change. Models may have underestimated this storm for today as it has come in a little stronger than thought, especially in the Lubbock area. Main round for us and Dallas area will be overnight tonight.
As far as roads, many accidents have occured within the last few hours. Sleet at 21 degrees is just not fun.
For anyone wanting to follow the conditions up here live, have two links below:
KOCO 5 news live:
http://www.koco.com/news/oklahomanews/w ... index.html
Reed Timmer out on the roads:
http://tvnweather.com/live
As far as roads, many accidents have occured within the last few hours. Sleet at 21 degrees is just not fun.
For anyone wanting to follow the conditions up here live, have two links below:
KOCO 5 news live:
http://www.koco.com/news/oklahomanews/w ... index.html
Reed Timmer out on the roads:
http://tvnweather.com/live
Blake
Boomer Sooner
Boomer Sooner
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Portastorm
- Posts: 800
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Belmer, thanks for the report and the links. Sounds like things are getting quite bad up there. Be safe! I'm guessing the weather conditions for Bedlam on Saturday are going to be awful. Who knows, Okie State's passing offense may be hampered and that would play in your school's favor!
Keep the reports coming.
Keep the reports coming.
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MontgomeryCoWx
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- Location: Weimar, TX
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Saturday/Sunday round of precip looking a lot healthier....
Team #NeverSummer
/\
Please do elaborate!
Please do elaborate!
Mike
Beaumont, TX
(IH-10 & College Street)
Beaumont, TX
(IH-10 & College Street)
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srainhoutx
- Site Admin
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Update from Jeff:
Arctic front clearly being felt across the region this afternoon with Galveston a balmy 72 and College Station 40.
Boundary has continued its southward push today and will reach the coast and pass offshore in the next few hours. Temperatures have been heading down quickly behind the frontal passage with many areas N of I-10 in the 40’s and the sub-40 degree line moving into the College Station and Huntsville areas. Freezing line is just nearing Dallas at this time with accumulations of ice and sleet ongoing just NW and N of Dallas and this will overtake much of N TX by this evening….things are going to get really bad in this part of the state tonight into Friday.
Expect to begin to see light to moderate rainfall develop later this evening as overrunning process begins to ramp up. Warm moist air will flow northward from the Gulf of Mexico over the top of the cold dome at the surface producing periods of rain. Surface temperatures will continue to fall all night as cold air advection brings the colder air from the north into the region. Could be very close to freezing by early Friday morning from College Station to Huntsville with some light icing possible. Given warm grounds do not think this is going to cause any major problems, but even a little ice on a bridge or overpass is dangerous. Much bigger concern is across N/NE TX where significant ice accumulation is almost certain at this point with major disruption to surface travel, air travel, and power expected.
NW of Columbus to Conroe to Livingston:
Cold air continues to filter southward on Saturday with high temperatures ranging from a couple degrees above freezing around College Station to 35-37 metro Houston to 39-42 along the coast. Next jet disturbance moves into the area late Saturday with another batch of light rain and drizzle. Surface temperatures are expected to cool to freezing NW of a line from Columbus to Hempstead to Conroe and this brings more of the area into the potential for freezing rain and light ice accumulation. A couple of factors we must consider:
1) The air above the surface is going to be very warm (40-50 degree range) and this will result in “warm” rain falling into the near surface freezing layer. With surface temperatures very marginal (30-32) from NW of Columbus to Livingston not sure we will see a whole lot of ice as the falling water itself is warm and will have to cool to the freezing point.
2) Ground temperatures are warm from the recent warm spell and will only slowly cool. Not expecting any ice at any time on surfaces in contact with the ground. Elevated surfaces such as trees, power lines, roof tops, bridge, and overpasses, vehicles stand the best potential for light icing
3) General precipitation amounts are expected to be light running in the .05 to .20 inch range. This precipitation must also fall when the surface temperature is at or below freezing to produce ice which will mainly be from roughly 700-900pm Saturday to about 900-1000am Sunday NW of a line from Columbus to Livingston.
The Harris County and the metro Houston Area:
Based on everything I have looked at this afternoon the surface temperature is forecast to be in the 33-37 degree range Saturday into Sunday morning which does not support any ice accumulation. Would not be totally surprised to see the far W/NW/N parts of the county drop to 32 or 31 Sunday morning, but think any icing will be very minor and short lived.
There remains uncertainty as to where exactly the freezing line will be at any given time period throughout the next 72 hours and this will have an effect on the potential impacts across the region. While this is technically the “magic line” between rain and ice, even locations that fall to freezing will likely only see minor impacts given the light amounts of precipitation expected and the warm grounds. With that said it does not take much ice to cause problems on bridges and overpasses.
Arctic front clearly being felt across the region this afternoon with Galveston a balmy 72 and College Station 40.
Boundary has continued its southward push today and will reach the coast and pass offshore in the next few hours. Temperatures have been heading down quickly behind the frontal passage with many areas N of I-10 in the 40’s and the sub-40 degree line moving into the College Station and Huntsville areas. Freezing line is just nearing Dallas at this time with accumulations of ice and sleet ongoing just NW and N of Dallas and this will overtake much of N TX by this evening….things are going to get really bad in this part of the state tonight into Friday.
Expect to begin to see light to moderate rainfall develop later this evening as overrunning process begins to ramp up. Warm moist air will flow northward from the Gulf of Mexico over the top of the cold dome at the surface producing periods of rain. Surface temperatures will continue to fall all night as cold air advection brings the colder air from the north into the region. Could be very close to freezing by early Friday morning from College Station to Huntsville with some light icing possible. Given warm grounds do not think this is going to cause any major problems, but even a little ice on a bridge or overpass is dangerous. Much bigger concern is across N/NE TX where significant ice accumulation is almost certain at this point with major disruption to surface travel, air travel, and power expected.
NW of Columbus to Conroe to Livingston:
Cold air continues to filter southward on Saturday with high temperatures ranging from a couple degrees above freezing around College Station to 35-37 metro Houston to 39-42 along the coast. Next jet disturbance moves into the area late Saturday with another batch of light rain and drizzle. Surface temperatures are expected to cool to freezing NW of a line from Columbus to Hempstead to Conroe and this brings more of the area into the potential for freezing rain and light ice accumulation. A couple of factors we must consider:
1) The air above the surface is going to be very warm (40-50 degree range) and this will result in “warm” rain falling into the near surface freezing layer. With surface temperatures very marginal (30-32) from NW of Columbus to Livingston not sure we will see a whole lot of ice as the falling water itself is warm and will have to cool to the freezing point.
2) Ground temperatures are warm from the recent warm spell and will only slowly cool. Not expecting any ice at any time on surfaces in contact with the ground. Elevated surfaces such as trees, power lines, roof tops, bridge, and overpasses, vehicles stand the best potential for light icing
3) General precipitation amounts are expected to be light running in the .05 to .20 inch range. This precipitation must also fall when the surface temperature is at or below freezing to produce ice which will mainly be from roughly 700-900pm Saturday to about 900-1000am Sunday NW of a line from Columbus to Livingston.
The Harris County and the metro Houston Area:
Based on everything I have looked at this afternoon the surface temperature is forecast to be in the 33-37 degree range Saturday into Sunday morning which does not support any ice accumulation. Would not be totally surprised to see the far W/NW/N parts of the county drop to 32 or 31 Sunday morning, but think any icing will be very minor and short lived.
There remains uncertainty as to where exactly the freezing line will be at any given time period throughout the next 72 hours and this will have an effect on the potential impacts across the region. While this is technically the “magic line” between rain and ice, even locations that fall to freezing will likely only see minor impacts given the light amounts of precipitation expected and the warm grounds. With that said it does not take much ice to cause problems on bridges and overpasses.
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey
Member: National Weather Association
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Portastorm
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Well, as Ed put it, the Dallas schoolkids are dancing in the streets ... if not sliding soon enough ... DISD has cancelled all classes for tomorrow.
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srainhoutx
- Site Admin
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15Z SREF ensemble members and the 18Z HIRES NAM for the overnight Saturday into early Sunday morning time frame...
15Z SREF:
SPC SREF Mean:
18Z HIRES NAM:
15Z SREF:
SPC SREF Mean:
18Z HIRES NAM:
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Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey
Member: National Weather Association
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vci_guy2003
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I keep hearing that next week is supposed tone so much colder, but the forecast shows highs in the 40s and 50s. Am I missing something?
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Katdaddy
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Well advertised strong cold front has moved through SE TX with significant temperature drops this afternoon. The KatDaddy weather station recorded a high temp of 79F at 11:54AM and its now down 47F at 6:30PM…..32F drop so far today. Also the well advertised Winter storm is also in progress over North Texas this evening. The SE TX freezing precip threat may come as close as far N and W Harris County.
18Z GFS is a problem for Harris County has IAH falling below freezing on Saturday and staying there into Sunday. This would shift the freezing rain threat southward. Still not really worried just yet as amounts look light and temperatures 31-32 on the 18Z run...also this is the first run to show this. It also has CLL reaching 24 by Sunday AM
Temperatures a few thousand feet above the surface will be in the 40's. Only the lowest 1000 ft or so will be "cold" so there will be no snow and sleet even seems remote. Main threat is freezing rain and mainly NW of a line from Columbus to The Woodlands to Livingston.hlewis wrote:I'm just going to go out on a limb here.... In Wharton County and having a parade in El Campo, any chance to see a lil snow flurry? Also, will rain be an issue between 5-9pm? I asked a day or so ago, but want to hear your thoughts now that we are getting close.
Last edited by jeff on Thu Dec 05, 2013 7:29 pm, edited 1 time in total.