March - Slow Warming Trend With Rain Chance This Weekend?

[Belmer]

One week from today marks a new month. Most importantly, it is the month we start looking down the road to warmer temperatures and severe weather. However, models are advertising a stormy/chilly pattern the first part of March. To me, I'm not ready for this winter to be over with quite yet. So bring on the cold!

[srainhoutx]

It certainly appears a very chilly start to March is ahead with freezing to near freezing temps well S into Texas and Louisiana. We will need to monitor these trends as freezing temps may come awfully close to the Coastal Counties late next week into next weekend.

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
200 AM EST SAT FEB 23 2013

VALID 12Z TUE FEB 26 2013 - 12Z SAT MAR 02 2013

...OVERALL PATTERN AND SENSIBLE WEATHER THREATS/HIGHLIGHTS...

THE MODELS AND ENSEMBLES POINT TO AN ACTIVE AND TRANSITIONAL
MEDIUM RANGE FLOW PATTERN STARTING TUE/WED INTO THU WITH THE
LIFTING OF A WELL ORGANIZED MID-UPPER LEVEL TROUGH AND SURFACE LOW
SYSTEM/WINTER WEATHER SWATH FROM THE MID-MS VALLEY TO THE
MIDWEST/GREAT LAKES/NE US AS MOISTURE WRAPS INTO THE SYSTEM...ALSO
THEN ENHANCED BY LAKE EFFECT. A TRAILING COLD FRONT APPROACH
ACROSS THE SE/ERN US WILL ALSO FOCUS PRECIPITATION.

MEANHWILE...ANOTHER DYNAMIC MID-UPPER LEVEL SHORTWAVE TROUGH DIGS
WINTER PCPN SEWD OVER THE WRN US MON/TUE BEFORE EJECTING EWD
ACROSS THE CENTRAL AND ERN STATES WED/THU...POSSIBLY LEADING TO
SOME EAST COASTAL SURFACE LOW RESPONSE. ANOTHER TROUGH IN THIS
SERIES IS ON ITS HEALS BACK ACROSS THE WEST MIDWEEK...BUT EXPECTED
RAPID UPSTREAM FLOW AMPLIFICATION OUT FROM THE ERN PACIFIC HAS
GOOD GUIDANCE SUPPORT TO LEAD TO DEVELOPMENT OF AN AMPLIFIED WRN
US MID-UPPER LEVEL RIDGE BY LATE NEXT WEEK. THIS MAY FORCE THE
LEAD IMPULSE TO AMPLIFY WITH NRN STREAM ENERGY INTO QUITE AN
AMPLIFIED AND COLD E-CENTRAL US MID-UPPER LEVEL TROUGH IN A
POSITIVE PNA PATTERN. DOWNSTREAM...TRENDS CONTINUED TOWARD AN
INCREASINGLY BLOCKY (NEGATIVE) NAO PATTERN EMERGING IN THE NRN
ATLANTIC HEADING INTO NEXT WEEKEND WITH HIGH LATITUDE HEIGHT RISES
FEEDING WWD ACROSS SRN GREENLAND TOWARD ERN CANADA.

...GUIDANCE EVALUATION AND WEATHER SYSTEM PREFERENCES...

MODEL AND ENSEMBLE MEAN GUIDANCE HAS OVERALL CONVERGED UPON A MORE
COMMON/BETTER CLUSTERED MID-LARGE SCALE SOLUTION FOR MUCH OF THE
FORECAST DOMAIN NEXT WEEK COMPARED TO THE LAST FEW DAYS WITH THE
LAST COUPLE GFS/GEFS RUNS MORE IN LINE/LESS PROGRESSIVE. LOWER
FORECAST SPREAD BOLSTERS FORECASTER CONFIDENCE DESPITE A
TRANSITIONAL PATTERN. THE ECMWF ENSEMBLE MEAN EVEN SO HAS PROVEN
THE MOST RUN TO RUN CONSISTENT THROUGH MEDIUM RANGE TIME SCALES
RECENTLY AND NOW SITS ON THE SLIGHTLY SLOWER/MORE AMPLIFIED SIDE
OF THE FULL ENVELOPE OF GUIDANCE ALOFT. THIS SOLUTION REMAINS
WELL SUPPORTED BY UPSTREAM AMPLITUDE OVER THE PACIFIC AS DEPICTED
IN RECENT WATER VAPOR IMAGERY LOOPS.

SCHICHTEL



00Z Euro Ensembles:

00Z NAEFS:

GGEM:

[srainhoutx]

With the strong N to NW flow aloft setting up over a building snow pack across the Southern Plains, it appears freezing overnight low temps may be possible for SE Texas mainly N of I-10 away from the urban heat areas early Saturday and Sunday. We will use this thread for local forecasts for the SE Texas area and keep Belmer's thread for our Regional Weather events during March.

[srainhoutx]

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
1023 AM EST MON FEB 25 2013

VALID 12Z THU FEB 28 2013 - 12Z MON MAR 04 2013

...GUIDANCE EVALUATION AND FORECAST CONFIDENCE ASSESSMENT...

HPC MEDIUM RANGE SURFACE FRONTS/PRESSURES AND 500 MB PROGS HAVE
BEEN PRIMARILY DERIVED FROM A 50-50 BLEND OF THE 00Z ECMWF/ECMWF
ENSEMBLE MEAN. THIS AMPLIFIED SOLUTION FITS RECENT GUIDANCE TRENDS
AND WATER VAPOR LOOPS... DOWNPLAYS SOME SMALLER SCALE FORECAST
VARIANCE... AND OFFERS GOOD HPC CONTINUITY AND REASONABLY GOOD
FORECAST CONFIDENCE. THE GFS/GEFS RUNS OFFER A SIMILAR BUT NOT
IDENTICAL SOLUTION THAT GENERALLY EITHER OUTPACED OR LAGGED THE
GREATER CLUSTERING OF THE ECMWF ENSEMBLES WITH THE UKMET AND
OCCASIONALLY THE CANADIAN MODEL... WITH THE 06Z GFS MUCH MORE OUT
OF STEP THAN ITS 00Z RUN.

...OVERALL FLOW PATTERN AND SENSIBLE WEATHER HIGHLIGHTS/THREATS...

A SHORT RANGE WINTER STORM PROGRESSES OUT FROM THE NERN US TOWARD
THE CANADIAN MARITIMES THU INTO FRI. THIS WILL SUPPORT LINGERING
WRAP-BACK SNOWS WITH MAX AMOUNTS OVER NRN NEW ENGLAND...
ESPECIALLY OVER FAVORED TERRAIN. LAKE EFFECT SHOULD PERSIST
THROUGH THE WEEKEND IN COLD FLOW IN THE WAKE OF THE LOW... WITH
LINGERING RAINS OVER SRN FL NEAR A TRAILING SLOWLY MOVING COLD
FRONT.

UPSTREAM...A DYNAMIC SHORTWAVE IMPULSE WITH LIMITED MOISTURE WILL
DROP SEWD THROUGH THE WRN US THU/D3. DIGGING ENERGY WILL FEED MORE
SHARPLY INTO THE S-CENTRAL US BY FRI TO THE LEE OF A RAPIDLY
AMPLIFYING MID-UPPER LEVEL E-CENTRAL PACIFIC TROUGH AND WRN US
RIDGE COUPLET DEVELOPING UPSTREAM. THIS LEADS TO QUITE AN
AMPLIFIED WRN US RIDGE AND COLD ERN US TROUGH... POSITIVE PNA
PATTERN... BY SAT/D5 JUST AS HEIGHT RISES FEED WESTWARD FROM
GREENLAND INTO ERN CANADA AT HIGHER LATITUDES. THIS MAY LEAD TO
ERN US COASTAL LOW POTENTIAL SAT-MON AND HPC MANUAL PROGS SHOW
MODERATE DEVELOPMENT BUT THE PATTERN FAVORS OFFSHORE DEVELOPMENT.
500MB STANDARDIZED HEIGHT ANOMALIES ARE FCST TO DROP TO -3.5 OR SO
CENTERED OVER FLORIDA OVER THE WEEKEND WITH SFC TEMPS 10-15 DEG F
BELOW NORMAL. TEMPERATURES IN THE WEST SHOULD BALANCE WITH HIGHS
WELL INTO THE 80S IN THE SW DESERTS.

MEANWHILE WELL UPSTREAM... AMPLIFIED ERN PACIFIC MID-UPPER LEVEL
TROUGH ENERGY REACHING THE NWRN US NEXT WEEKEND WILL WORK INTO THE
LEAD WRN US MID-UPPER LEVEL RIDGE AND FAVOR ANOTHER CHANCE FOR
ORGANIZED PCPN. GUIDANCE OFTEN BREAKS DOWN AMPLIFIED BLOCKY RIDGES
TOO RAPIDLY WITH APPROACHING TROUGHS...BUT HPC MANUAL PROGS AT
LEAST TAKE INTO ACCOUNT THAT THE SPECIFIC SYSTEM INVOLVED OFFERS
QUITE A BIT OF MUSCLE NOW OFF JAPAN. BELIEVE THE MAJORITY OF THE
ENERGY SHOULD FUNNEL INTO VANCOUVER ISLAND BEFORE DIVING THROUGH
THE HIGH PLAINS MON/D7... THOUGH THE DETERMINISTIC ECMWF LIES ON
THE STRONGER SIDE OF THE ENSEMBLES BY CLOSING OFF AN UPPER LOW BUT
OTHERWISE STILL CORRELATES WELL WITH ITS MEAN.

SCHICHTEL/FRACASSO


And just for fun, the 12Z la la land GFS spits out a 1053mb Arctic High dropping S into Colorado near the second week of March...

[Ptarmigan]

It is not unheard of to see freezes in March.

Freezes In March from 1921 to 2012 (Lows 32°F or less)
1922-March 1-3
1923-March 19-20
1932-March 9-13 Only March snowfall recorded in Houston on March 10, 1932.
1938-March 18
1943-March 2-3, 7
1947-March 2
1948-March 11-13
1951-March 13
1955-March 26-27
1960-March 3-4
1965-March 20
1970-March 14, 22
1971-March 3-4, 7-8, 20
1978-March 3-5, 9-10
1980-March 1-3
1984-February 28-March 1
1989-March 4-9
1993-March 13-14 Start of the Great Storm of 1993.
1996-March 8-10
2002-March 2-5

The coldest March day is 21°F on March 3, 1943.

http://www.srh.noaa.gov/hgx/?n=climate_iah_normals_mar

[Belmer]

12z GFS paints some wintery fun for Central TX overnight Friday into Saturday morning. As much as I want to get excited, I just think it will be too dry in the lower levels for anything to reach the ground.

[srainhoutx]

There continues to be strong signals via the CFSv2/NAEFS/European/GGEM ensemble guidance that a strong blocking regime will develop over the N Atlantic and extend W into Eastern Canada. The AO appears to drop to a strongly negative pattern achieving 4-5 standard deviations below normal with a very-EPO regime with a strong + PNA developing over the Pacific. Generally when we see such a pattern developing at the 500mb level, a much colder regime becomes established across North America. The wild card in such a pattern is can we get some moisture and will the sub tropical jet become very noisy? That remains to be seen. Usually a Kona Upper Low develops near Hawaii that taps moisture/convection near the dateline a drives that moisture toward the Baja. All that said to say I do believe that Winter has one more shot to offer the cold weather lover a reprieve before a Spring like pattern finally develops around mid to late March. We will see.

[Portastorm]

There continues to be strong signals via the CFSv2/NAEFS/European/GGEM ensemble guidance that a strong blocking regime will develop over the N Atlantic and extend W into Eastern Canada. The AO appears to drop to a strongly negative pattern achieving 4-5 standard deviations below normal with a very-EPO regime with a strong + PNA developing over the Pacific. Generally when we see such a pattern developing at the 500mb level, a much colder regime becomes established across North America. The wild card in such a pattern is can we get some moisture and will the sub tropical jet become very noisy? That remains to be seen. Usually a Kona Upper Low develops near Hawaii that taps moisture/convection near the dateline a drives that moisture toward the Baja. All that said to say I do believe that Winter has one more shot to offer the cold weather lover a reprieve before a Spring like pattern finally develops around mid to late March. We will see.

Well, there are a handful of recorded March snow events in Austin in the last 100 years or so. And for Houston, I work with a guy whose two kids were born in Houston in March and it snowed on both days. And we all know that March can still deliver sub-freezing temperatures deep into the heart of Texas. The date of the average last freeze in Austin is right about now (late Feb/early Mar) but recorded freezes have occurred well into April.

All of this to say: bring it!

[Ptarmigan]

There continues to be strong signals via the CFSv2/NAEFS/European/GGEM ensemble guidance that a strong blocking regime will develop over the N Atlantic and extend W into Eastern Canada. The AO appears to drop to a strongly negative pattern achieving 4-5 standard deviations below normal with a very-EPO regime with a strong + PNA developing over the Pacific. Generally when we see such a pattern developing at the 500mb level, a much colder regime becomes established across North America. The wild card in such a pattern is can we get some moisture and will the sub tropical jet become very noisy? That remains to be seen. Usually a Kona Upper Low develops near Hawaii that taps moisture/convection near the dateline a drives that moisture toward the Baja. All that said to say I do believe that Winter has one more shot to offer the cold weather lover a reprieve before a Spring like pattern finally develops around mid to late March. We will see.

Well, there are a handful of recorded March snow events in Austin in the last 100 years or so. And for Houston, I work with a guy whose two kids were born in Houston in March and it snowed on both days. And we all know that March can still deliver sub-freezing temperatures deep into the heart of Texas. The date of the average last freeze in Austin is right about now (late Feb/early Mar) but recorded freezes have occurred well into April.

All of this to say: bring it!

The only March snowfall to happen in Houston was in 1932. However, there have been freezes in March in Houston.

Freezes In March from 1921 to 2012 (Lows 32°F or less)
1922-March 1-3
1923-March 19-20
1932-March 9-13 Only March snowfall recorded in Houston on March 10, 1932.
1938-March 18
1943-March 2-3, 7
1947-March 2
1948-March 11-13
1951-March 13
1955-March 26-27
1960-March 3-4
1965-March 20
1970-March 14, 22
1971-March 3-4, 7-8, 20
1978-March 3-5, 9-10
1980-March 1-3
1984-February 28-March 1
1989-March 4-9
1993-March 13-14 Start of the Great Storm of 1993.
1996-March 8-10
2002-March 2-5

[Katdaddy]

Hmmmm......

From this mornings Houston-Galveston AFD:

THE ONLY MENTIONABLE
PRECIPITATION CHANCES WILL OCCUR LATE FRIDAY OR EARLY SATURDAY
ACROSS THE WESTERN CWA. A SHORTWAVE DISTURBANCE DIVING SOUTH ALONG
THE BACKSIDE OF NORTHEASTERN U.S. TROUGHING FRIDAY...IN LINE WITH
A REINFORCING COLD FRONT...WILL TRACK STRAIGHT DOWN INTO THE COASTAL
BEND. THERE MAY BE ENOUGH LIFT...WITH A MOIST ENOUGH DOWNSTREAM
ENVIRONMENT (AROUND 0.5 INCH PWATS)...TO INITIATE VERY LIGHT
PRECIPITATION (-SN) WITHIN A SUB-FREEZING AIR MASS. 1000-500MB
THICKNESS VALUES IN THE LOWER 530 DAMS ARE FORECAST TO REACH THE
MATAGORDA BAY REGION WITH FRIDAY NIGHT/SATURDAY MORNING NEGATIVE
SINGLE DIGIT 85H TEMPERATURES. PWAT VALUES ARE NOT EXTREMELY HIGH
BUT WESTERN-SOUTHWESTERN FORECAST AREA SOUNDINGS DO SHOW DEEP
ENOUGH BELOW FREEZING MID-LEVEL SATURATION IN SUPPORTING VERY
LIGHT SNOW OR FLURRIES. THE MAIN QUESTION WILL BE WHETHER THERE
WILL BE ENOUGH LIFT FROM EITHER THE SHORTWAVE (VORT MAX)...OR FROM
FALLING INTO A MORE-FAVORABLE LF QUAD WITHIN A NORTH-SOUTH JET
SPEED MAX...IN GENERATING ANY PRECIPITATION AT ALL. ALTHOUGH
SURFACE TEMPERATURES WILL BE SLIGHTLY ABOVE FREEZING...FEEL THERE
COULD BE ENOUGH LOWER LEVEL ZERO WET-BULBING TO DRIVE THEM DOWN
TO NEAR FREEZING THROUGH MIDNIGHT SATURDAY.

[srainhoutx]

The first day of March looks very chilly as another cold front passes SE Texas early Friday. The fly in the ointment that has been present for several days via the GFS/Euro/Ukmet is a vort max/strong short wave diving due S from the Plains and will cross our Forecast area mainly W of the I-45 Corridor to the Coastal Bend late Friday afternoon/early Saturday. The forecast soundings indicate very cold air aloft with just enough lift and a saturated column with our area in a favorable left front quadrant to generate some moisture. HGX has mentioned the possibility of some of this moisture making it to the surface. The temp profiles throughout the column indicate light snow/snow flurries are possible during the overnight hours. Surface temps appear to be border line or just above freezing, but due to the strong cold air advection over the heavy snow pack to our N from the Blizzard earlier this week it may be worth monitoring. The one issue that will have to be overcome is a very dry layer below 3000 to 5000 feet. While HGX is mentioning that enough saturation may occur, my hunch is that virga will be the most likely outcome with maybe a flurry or two reaching the ground. We will monitor the trends as we get closer during the next 24-48 hours. It is interesting to note the the NOAA G-IV is scheduled to make some drops as it departs Hawaii on its return flight to their home base in Tampa overnight. Saturday looks cloudy and cold as temps struggle to reach the mid 50's with freezing to near freezing temps expected away from the urban heat island areas overnight Saturday/early Sunday.

[txflagwaver]

Hmmm...did someone say the "S" word??

Great to have our local weather easy to get to. Other areas are great for a hobby but unless I am traveling, I need my local info...

Thanks S'rain!

[wxman57]

I see that the 06Z GFS dropped that nonsense about snow near Houston Fri/Sat. Euro hasn't indicated anything in the past few runs. 06Z GFS does predict snow for Tampa next Monday (right). March is almost here. Time to start thinking about 80+ deg temps, not snow.

However, I see neither snow nor 80F temps in our immediate future.

[srainhoutx]

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
1057 AM EST WED FEB 27 2013

VALID 12Z SAT MAR 02 2013 - 12Z WED MAR 06 2013

...OVERVIEW AND PREFERENCES...

THE MEDIUM RANGE PERIOD WILL SEE A MODERATELY STEADY PROGRESSION
OF SYSTEMS FROM THE PACIFIC ACROSS THE CONUS. A PERSISTENT MEAN
RIDGE OVER ERN CANADA WILL SUPPORT A FAIRLY AMPLIFIED ERN CONUS
MEAN TROUGH... WITH ACCOMPANYING CHILLY TEMPS... ALBEIT WITH A
GRADUAL TREND TOWARD INCREASING HGTS ALOFT IN THE MEAN. FARTHER
WWD A MODEST MEAN RIDGE FCST TO BUILD BETWEEN ALASKA AND HAWAII
LATE IN THE PERIOD MAY ENCOURAGE SOME DEGREE OF MEAN TROUGHING
OVER THE WEST AROUND THE MIDDLE OF NEXT WEEK.

OPERATIONAL MODELS/ENSEMBLES SHOW BETTER THAN AVERAGE AGREEMENT
WITH TIMING OF THE MOST SIGNIFICANT FEATURES BUT CONFIDENCE IS
LOWER IN SOME OPERATIONAL MODEL DETAILS. BASED ON THE CURRENT
ARRAY OF GUIDANCE ALONG WITH RECENT TRENDS AND HPC CONTINUITY... A
BLEND OF THE 00Z GEFS/ECMWF ENSEMBLE MEANS WITH MINORITY
ENHANCEMENT FROM AN AVG OF 00Z/27 AND 12Z/26 ECMWF RUNS PROVIDES
THE BEST STARTING POINT FOR THE DAYS 3-7 SAT-WED PERIOD.


...GUIDANCE EVALUATION...

THE FCST FEATURES THREE DOMINANT MID LVL SYSTEMS... AN AMPLIFIED
ERN CONUS TROUGH THAT SHOULD PROGRESS INTO THE ATLC BY LATE DAY 5
MON... AN ERN PAC SHRTWV THAT SHOULD ENTER THE WEST ON SUN AND
APPROACH THE EAST COAST BY NEXT WED... FOLLOWED BY A TROUGH/PSBL
EMBEDDED CLOSED LOW REACHING THE WEST COAST NEXT WED.

INDIVIDUAL MODELS/ENSEMBLES INDICATE A DECENT AMOUNT OF
UNCERTAINTY FOR THE HANDLING OF MULTIPLE PIECES OF ENERGY WITHIN
THE INITIAL ERN CONUS MEAN TROUGH. OVER THE PAST 1-2 DAYS
INDIVIDUAL GFS RUNS HAVE TENDED TO BE MORE VARIABLE THAN ECMWF
RUNS AND LESS AGREEABLE WITH ENSEMBLE MEANS... FAVORING EMPHASIS
ON LATEST ENSEMBLE MEANS AND RECENT OPERATIONAL ECMWF RUNS. AS
THIS TROUGH EVENTUALLY DEPARTS FROM THE EAST THE BEST DEFINED SFC
LOW PRESSURE SHOULD EVOLVE WELL OFFSHORE OVER THE ATLC.

AS THE UPSTREAM SHRTWV REACHES THE WEST COAST SUN THE BEST
MODEL/ENSEMBLE CONSENSUS SUGGESTS THE CORE OF MID LVL ENERGY
SHOULD TRACK SOMEWHAT NWD OF THE 00Z/06Z GFS RUNS. ENSEMBLE MEANS
AND OPERATIONAL MDLS HINT AT THE ECMWF PSBLY BEING A LITTLE
SLOW/TOO POSITIVELY TILTED WITH THE MID LVL SYSTEM AROUND DAYS 5-6
MON-TUE. AS THE SYSTEM HEADS INTO THE CNTRL-ERN CONUS THE MEAN
RIDGE OVER ERN CANADA SUPPORTS A MODERATELY SUPPRESSED SFC LOW
TRACK WITH THE PAST COUPLE DAYS OF GEFS MEAN RUNS TRENDING SWD
TOWARD RECENT ECMWF MEANS AS OF DAY 6 TUE. LATE IN THE PERIOD THE
00Z ECMWF OFFERS A LOW PROBABILITY SOLN INVOLVING PHASING THE
SHRTWV OF INTEREST AND LINGERING GRTLKS ENERGY TO YIELD A DEEP
EAST COAST LOW BY LATE WED. AS OF LATE WED THE 00Z ECMWF IS ON
THE WRN EDGE OF THE ENSEMBLE SPREAD... WHICH SPANS FROM THE SERN
COAST TO OVER/E OF LONG ISLAND AND THEN OFFSHORE INTO THE ATLC. A
LAGGED AVG OF RECENT ECMWF RUNS IS SOMEWHAT FASTER THAN THE 00Z
RUN THOUGH A LITTLE S OF THE 12Z/26 RUN. THE 06Z GFS MAY BE TOO
FAR N WITH ITS SFC TRACK UNTIL LATE WED. THE 00Z GFS IS IN THE
SRN PART OF THE SPREAD AS ITS SFC LOW TRACKS OFF THE SERN COAST.

THE FINAL SYSTEM OF INTEREST IS EXPECTED TO BE A NRN PAC/ALEUTIANS
CLOSED LOW DROPPING SEWD TOWARD THE WEST COAST LATE IN THE
PERIOD... POSSIBLY OPENING UP AS IT REACHES THE WEST COAST BY WED.
MODELS/ENSEMBLES AGREE WELL WITH TIMING OF THE ASSOC SFC LOW BUT
VARY WIDELY ON LATITUDE. THE 00Z GFS IS NEAR THE SRN EDGE OF THE
SPREAD WITH ITS ERN PAC SFC LOW EARLY WED WITH A COMPROMISE
BETWEEN THE 00Z ECMWF AND 06Z GFS ULTIMATELY PREFERRED. THE
12Z/26 ECMWF WAS SIMILAR IN POSN TO THE 06Z GFS. ENSEMBLE MEANS
HAVE BEEN TRENDING A LITTLE FASTER WITH THE MID LVL TROUGH OVER
THE PAST 1-2 DAYS. AS OF DAY 7 WED THE GEFS MEANS HAVE BEEN
TRENDING STRONGER TOWARD THE PAST THREE ECMWF MEAN RUNS TO YIELD
MORE SIMILAR FCSTS AS OF THE 00Z RUN.


...SENSIBLE WEATHER HIGHLIGHTS...

EXPECT MAINLY LGT/SCT PCPN UNDER THE INITIAL ERN CONUS TROUGH
ALOFT. BELOW NORMAL TEMPS WILL BE THE PRIMARY HIGHLIGHT DURING
THE SAT-MON PERIOD WITH A BROAD AREA OF DAYTIME HIGHS 10-20 F
BELOW NORMAL OVER THE ERN HALF OF THE LOWER 48 ESPECIALLY SAT-SUN.
COLDEST MORNING LOWS... 10-15 F BELOW NORMAL... SHOULD EXTEND
FROM THE CNTRL PLAINS INTO THE MS VLY AND THEN SOUTHEAST
CORRESPONDING TO MOVEMENT OF SFC HIGH PRESSURE.

SYSTEM MOVING THRU THE WEST DURING THE FIRST HALF OF THE PERIOD
WILL BRING A BROAD PCPN SHIELD ACROSS THE AREA DURING THE WEEKEND
WITH BEST FOCUS OVER FAVORED TERRAIN IN THE NRN THIRD OF THE WEST.
DECENT DYNAMICS MAY SUPPORT LOCALIZED/BRIEF INTENSE ACTIVITY BUT
IN AREAL AVG TERMS PCPN AMTS SHOULD BE MODERATE. THIS SYSTEM
SHOULD SUPPORT A BAND OF COLD SECTOR SNOW OVER PORTIONS OF THE
CNTRL-ERN STATES BY NEXT MON-WED. PINPOINTING GREATEST IMPACT
WILL IMPROVE ONCE GUIDANCE COMES INTO BETTER AGREEMENT FOR A SFC
LOW TRACK. WARM SECTOR RNFL SHOULD BE LIGHTER THAN IN PREVIOUS
EVENTS DUE TO MORE MODEST AND/OR BRIEF GULF INFLOW.

AMPLITUDE OF THE FINAL SYSTEM OF THE PERIOD MAY SUPPORT A FARTHER
SWD PUSH OF MSTR OVER CA THAN SEEN WITH THE PRECEDING FEATURE...
WITH THE CNTRL WEST COAST CURRENTLY THE MOST FAVORED AREA FOR
HIGHEST PCPN TOTALS DURING NEXT TUE-WED.

RAUSCH

[JackCruz]

Anything for Houston? No? Okay cool *exits*

[wxman57]

12Z GFS has the low (2m) temp at IAH 39 from Thu through Sunday. No freeze at IAH. Also, not a single drop of rain in the next 7 days.

[srainhoutx]

Afternoon e-mail from Jeff:

Secondary surge of high pressure has crossed the region this afternoon with an increase in NW winds and advection of another dry air mass. Very little change in the pattern over the next few days as dry NW flow aloft remains in place with another frontal passage on Friday afternoon.

Friday afternoon frontal passage will usher in a cold air mass with sub-freezing 850mb temperatures all the way to the coast. Model guidance suggest a very strong upper air disturbance rides down the backside of the main eastern US trough across the heart of TX late Friday night into Saturday morning. The air mass over the region will be very dry in the low levels, but strong lift along with cold temperatures aloft could generate favorable conditions for a few flurries especially around Matagorda Bay where moisture will be the greatest. Current thinking is pointing toward a very dry surface layer with most of what falls evaporating before hitting the ground. Latest GFS has trended drier with the short wave with any chance of flurries less than 20%.

As for temperatures, dewpoints falling into the upper 20’s and lower 30’s will support surface temperatures near freezing both Saturday and Sunday mornings mainly north of I-10 and away from the major urban heat cores. Still with spring green up in progress already, some tender vegetation could get burned if not protected.

Otherwise cool and dry for the next 5-7 days.

[jasons2k]

NWS has raised my weekend lows from 32 up to 35. Coldest night changed to tomorrow night at 34. I can't recall the last time I saw so much switching around of the coldest night and jumping from low-mid-high 30's. I suppose it speaks to the progressive pattern & lots of changes. Oh well, when it's all said and done, if we bottom-out at 34, I'll take it. I just want to get back to a return flow pattern soon. All this nonstop cold, dry, & windy cr@p is for the birds. I want my Houston weather back

[srainhoutx]

The 500mb pattern suggests a rapid flow from the NW with fronts dropping across the Region every 24-36 hours into early next week. A very extreme blocking High Pressure Ridge (1080+) is developing over Greenland and will extend W to near Hudson Bay early next week. A very deep trough with the western fringe of the axis remains overhead across the Southern Plains and the base of the trough extends well S into the Gulf/Northern Caribbean Sea virtually shutting down any return flow possibilities from the Gulf for the next 7 days. Pacific Storms will ride up and over the Ridge of High Pressure that is in place across the Pacific from Hawaii to Alaska. These storms will head inland across British Columbia and the Pacific NW (Washington/Oregon) early in the period before diving S into the Plains along the W flank of the trough. This pattern should persist until around the March 8th, +/- a couple of days when the Pacific Ridge breaks down and strong storm approaches the California Coast offering a bit of a pattern change and hopefully a shot at some much needed rainfall. It is noteworthy that the NOAA G-IV will depart Honolulu this afternoon and make drops every 150 NM miles across the EPAC as it returns to its home base at MacDill AFB in Tampa.

NOUS42 KNHC 271647
REPRPD
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1145 AM EST WED 27 FEBRUARY 2013
SUBJECT: WINTER STORM PLAN OF THE DAY (WSPOD)
VALID 28/1100Z TO 01/1100Z MARCH 2013
WSPOD NUMBER.....12-089

I. ATLANTIC REQUIREMENTS
1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

II. PACIFIC REQUIREMENTS
1. FLIGHT ONE --NOAA 49--
A. P-99/ 125.0W/ 01/0000Z
B. NOAA9 18WSC TRACK99
C. 28/1900Z
D. DROPS EVERY 150NM ALONG TRACK BETWEEN
150.OW AND 125.0W
E. AS HIGH AS POSSIBLE/ 01/0600Z

2. SUCCEEDING DAY OUTLOOK.....NEGATIVE.



EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
200 AM EST THU FEB 28 2013

VALID 12Z SUN MAR 03 2013 - 12Z THU MAR 07 2013

...PATTERN OVERVIEW...

THE MEDIUM RANGE PERIOD WILL SHOW A RENEWAL OF AN ACTIVE WINTER
PATTERN AS A MODERATELY STEADY PROGRESSION OF SYSTEMS EMERGES FROM
THE PACIFIC OVER THE US. THIS FLOW FEATURES THREE DOMINANT AND
STEADILY PROGRESSIVE MID-UPPER LEVEL SYSTEMS. THESE INCLUDE AN
AMPLIFIED ERN US TROUGH THAT EXITS INTO THE WRN ATLC MON...AN ERN
PACIFIC TROUGH THAT TRACKS SEWD FROM THE WRN US SUN THROUGH THE
CENTRAL US MON-TUE THEN TO ERN/SERN US COAST THEN WRN ATLANTIC
WED/THU...AND AN UPSTREAM AMPLIFIED TROUGH THAT SLAMS INLAND INTO
THE WRN US NEXT WED/THU.

...GUIDANCE AND UNCERTAINTY EVALUATION...

GUIDANCE OVERALL HAS BELOW NORMAL FORECAST SPREAD AND UNCERTAINTY
BEYOND SMALL SCALES SUN-TUE BEFORE OFFERING GREATER VARIANCE NEXT
WED/THU...BUT EVEN SO WITH A REASONABLY SIMILAR LARGE SCALE PLAN
THAT REMAINED PRETTY CONSISTENT OVER THE PAST FEW DAYS SO THAT IS
ENCOURAGING. WHILE GUIDANCE CERTAINLY CONTINUES TO HAVE TOO MANY
BAD DAYS...ESPECIALLY WITH SENSIBLE WEATHER FOCUS...IT IS
REMARKABLE HOW MUCH IMPROVEMENT HAS OCCURRED AT MEDIUM RANGE TIME
SCALES OVER THE YEARS. THIS HAS BEEN ESPECIALLY EVIDENT WITH
MODEL UPGRADES AND THE ADVENT OF MULTIPLE ENSEMBLE SYSTEMS THAT
COMBINE TO SHOW QUITE A REPRESENTATIVE RANGE/FREQUENCY OF
SOLUTIONS AND THREATS FOR A FORECASTER TO PONDER AND IMPROVE UPON.

TODAYS HPC MEDIUM RANGE SURFACE FRONTS/PRESSURES AND 500 MB PROGS
AND ASSOCIATED SENSIBLE WEATHER 5KM GRIDS HAVE BEEN PRIMARILY
DERIVED FROM A NEAR EQUAL COMPOSITE BLEND OF COMPATABLE 12 UTC
GFS/ECMWF AND GFS/ECMWF ENSEMBLE MEAN GUIDANCE SUN-TUE BEFORE
LEANING THE BLEND MUCH MORE ON THE ECMWF ENSEMBLE MEAN BY NEXT
WED/THU AMID GROWING FORECAST SPREAD...ALL ALBEIT WITH PONDERED
FORECASTER ADJUSTMENTS. THIS RESULTANT SOLUTION STRONGLY KEEPS IN
MIND HPC CONTINUITY THAT REMAINS WELL MAINTAINED.

...SENSIBLE WEATHER HIGHLIGHTS/THREATS...

EXPECT MAINLY LIGHT AND SCATTERED PCPN UNDER THE LEAD ERN CONUS
TROUGH ALOFT SUN/MON WITH LINGERING SNOWS WRAPPED TO MAINE AND
WITH LAKE EFFECT IN THE COLD AIR ACROSS MUCH OF THE CENTRAL AND
ERN/SERN US.

MEANWHILE...THE NEXT SYSTEM MOVING THRU THE WEST SUN INTO MON WILL
BRING A BROAD PCPN SHIELD ACROSS THE AREA WITH BEST FOCUS OVER
FAVORED TERRAIN IN THE NRN THIRD OF THE WEST. DECENT DYNAMICS MAY
SUPPORT LOCALIZED/BRIEF INTENSE ACTIVITY BUT IN AREAL AVERAGE
TERMS PCPN AMOUNTS SHOULD BE MODERATE. THIS SYSTEM SHOULD SUPPORT
A BAND OF COLD SECTOR SNOW OVER PORTIONS OF THE CENTRAL-ERN US
MON-WED. WARM SECTOR RAINFALL SHOULD BE LIGHTER THAN PREVIOUS
EVENTS DUE TO MODEST GULF INFLOW. THE BIG THREAT QUESTION REMAINS
THE EXTENT OF STREAM PHASING AND THE POTENTIAL FOR DEEP SURFACE
LOW DEVELOPMENT CLOSER TO THE S-CENTRAL APPALACHIANS AND
MID-ATLANTIC/CAROLINAS BY NEXT MIDWEEK. THE LAST FEW ECMWF RUNS
HAVE BEEN STRONGEST WITH THE FEATURE BUT SEEM TO OVERPLAY PHASING
GIVEN STREAM DETAIL UNCERTAINTY. HPC PROGS OFFER MORE MODEST
DEVELOPMENT CURRENTLY...BUT THERE IS INCREASING ENSEMBLE SUPPORT.

WELL UPSTREAM...EXPECTED HIGH AMPLITUDE OF THE FINAL SYSTEM OF THE
PERIOD SHOULD HIGHLIGHT A MORE WIDESPREAD AND FARTHER SWD EXTENT
OF MOISTURE/PCPN DOWN OVER THE WEST COAST INTO CA AND INLAND INTO
THE INTERMOUNTAIN WEST TUE-THU THAN SEEN WITH THE PRECEDING
FEATURE.

SCHICHTEL

[srainhoutx]

The over night guidance has come in a bit colder for the Friday/Saturday time frame suggesting temps on Saturday may struggle to get out of the 40’s across SE Texas with cloudy skies and blustery N/NW winds behind a strong cold front Friday. The GFS and NAM as well as the Euro do suggest a hint of lift and moisture aloft in the form of snow, but very dry lower levels would have to be overcome for any of that frozen moisture to make it to the surface. Virga with an isolated flurry/sleet pellet or two may be possible. The major concern is the freezing temps expected Saturday night/Sunday morning. The best chance of freezing temps will be away from the Urban Heat Island areas. Temps may well dip into the mid to upper 20’s for the outlining areas N of I-10 and in the upper 20’s along the SW areas of the HWY 59 Corridor.