Wx Infinity Forums

Above normal temps and near normal rainfall, hopefully...

HGX seems to think rain chance will increase Sunday into Monday/early Tuesday as well...

EARLY SATURDAY...THIS MID-LEVEL TO SURFACE ZONE OF CONVERGENCE
WILL INCREASE POPS TO SLIGHT (LOW QPF) ACROSS THE FAR NORTHERN
CWA. ENSEMBLE TAKES THIS BOUNDARY TOWARDS THE COAST THROUGH THE
DAY...BACKING EASTERLY WINDS AND SLIGHT CHANCE POPS (ISOLATED
SHOWERS) UNDER CLOUDIER SKIES WILL WILL TAKE US INTO SUNDAY. THE
NEXT SIGNIFICANT UPPER TROUGH WILL TRAVEL OUT OF THE PAC NW LATE
IN THE WEEKEND...INTO THE ROCKIES BY EARLY MONDAY. THUS...MOISTURE
PUMP KICKS IN SUNDAY WITH A GOOD DAY OR TWO TO SATURATE THE ATMOSPHERE
AHEAD OF THIS NEXT SIGNIFICANT COLD FROPA. ATTM...5H TROUGH FORECAST
TO DIG DEEPER INTO THE SOUTHERN PLAINS AND PUSH A STRONGER MID-SFC
BOUNDARY THROUGH LATE MONDAY INTO EARLY TUESDAY. GFSBUFR SOUNDINGS
ERODE WARM NOSE AND PRODUCE VERY GOOD CAPE/L.I.S LATE MONDAY AFTERNOON
INTO EVENING. ENVIRONMENT SEEMS TO BE BETTER PRIMED FOR ACTIVE
WEATHER IF A S/W RIDES UP RIGHT AHEAD OF THE FRONT...OR AREA FALLS
UNDER EFFICIENT UPPER DIV.

The 12Z GFS suggests some rain chances for next Monday evening/Tuesday morning, if the cap can break...sound familiar...

HGX mentions areas N and E of us for early next week. I did find it interesting that the forecaster is noting this may be a big severe weather event as well...

AS WE START THE NEW WORK WEEK...MONDAY LOOKS TO BE BREEZY AHEAD OF THE
NEXT STORM SYSTEM THAT COMES THROUGH THE AREA MONDAY NIGHT/TUESDAY MORNING.
WE ARE ALREADY CARRYING CHANCE POPS FOR THIS EVENT...AND THIS STILL
LOOKS GOOD. THIS STORM SYSTEM HAS THE POTENTIAL TO BE A BIG SEVERE
WEATHER PRODUCER...ESPECIALLY NORTH THROUGH NORTHEAST OF OUR AREA
AND EVENTUALLY ALONG THE EASTERN U.S. COAST AND THE NORTHEASTERN
STATES. WILL WE GET ANY SEVERE HERE? WE SHALL SEE.

I would like to see below normal temperatures and above normal rainfall for April.

Ptarmigan wrote:I would like to see below normal temperatures and above normal rainfall for April.

It is already too cold.

Could be some rain next Monday night, followed by more 40s for lows for a few days.

wxman57 wrote:Could be some rain next Monday night, followed by more 40s for lows for a few days.

Perfect starwatching weather.

Although this will change as we get closer and our area is not included, the SPC is certainly concerned about a potential big severe weather outbreak for next week...

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0409 AM CDT THU MAR 31 2011

VALID 031200Z - 081200Z

...DISCUSSION...

SOME TIMING AND AMPLITUDE DIFFERENCES PERSIST AMONG GFS...ECMWF AND
ENSEMBLE MEMBERS. HOWEVER...MODELS HAVE GENERALLY CONVERGED TOWARD A
SIMILAR SOLUTION REGARDING UPPER TROUGH FORECAST TO AMPLIFY AND MOVE
INTO THE PLAINS LATE DAY 4...THEN MS/OH VALLEYS AND SERN STATES DAY
5 AND FINALLY ATLANTIC COASTAL REGION DAY 6. IT APPEARS THIS FEATURE
WILL REMAIN A PROGRESSIVE UPPER WAVE AS IT ADVANCES THROUGH THE ERN
2/3 OF THE COUNTRY.

...DAY 4...

LLJ ASSOCIATED WITH CNTRL PLAINS LEE CYCLONE WILL CONTINUE ADVECTING
RICHER GULF MOISTURE THROUGH WARM SECTOR ACROSS THE SRN-CNTRL PLAINS
AND LOWER-MID MS VALLEY. EML WILL EXPAND EWD AND EFFECTIVELY CAP
WARM SECTOR EAST OF DRYLINE OVER THE PLAINS. HOWEVER...POTENTIAL
WILL EXIST FOR IMPULSE TO EJECT EWD AHEAD OF MAIN UPPER TROUGH.
DIABATIC WARMING OF THE BOUNDARY LAYER AND DRYLINE CONVERGENCE MIGHT
BECOME SUFFICIENT FOR ISOLATED SUPERCELLS FROM KS SWD INTO OK AND
NRN TX. ADDITIONAL STORMS WILL BE MORE LIKELY AS THE COLD FRONT
ADVANCES SEWD AND INTERCEPTS THE DRYLINE FROM THE CNTRL PLAINS INTO
THE MID MS VALLEY AREA.

...DAY 5...

WIDESPREAD SEVERE STORMS ARE BECOMING INCREASINGLY PROBABLE DAY 5.
GULF MOISTURE WILL ADVECT NWD THROUGH LOWER-MID MS VALLEY...SERN
STATES AND OH VALLEY IN ASSOCIATION WITH VERY STRONG EWD MIGRATING
LLJ. MORE WIDESPREAD THUNDERSTORM DEVELOPMENT WILL BECOME PROBABLE
AS FORCING FOR DEEP ASCENT ATTENDING THE UPPER TROUGH SHIFTS EAST OF
STRONGER EML. THREAT WILL EXIST FOR SUPERCELLS AND LINE SEGMENTS
WITH TORNADOES...LARGE HAIL AND DAMAGING WIND.

...DAY 6...

SEVERE THREAT SHOULD CONTINUE THROUGH THE REMAINDER OF THE SERN
STATES AND THE MID ATLANTIC SEABOARD.

..DIAL.. 03/31/2011

wxman57 wrote:Could be some rain next Monday night, followed by more 40s for lows for a few days.

Woo Hoo.....

Severe chances don't look too good as the best rain chances will be from midnight to 6am Tuesday. That may even diminish the rain chances, but I think we may have a good chance for some widespread amounts of .25 to .5 inch ahead of the front.

May see low-mid 40s Wednesday morning followed by a quick warm-up.

wxman57 wrote: May see low-mid 40s Wednesday morning followed by a quick warm-up.

Maybe making a run at 90 late next week?

That far away, I think there's still a wide margin on the front's timing. Maybe we'll get more lucky than the midnight to 6am slot.

Timing on the front now looks a bit earlier. Overnight GFS runs are 6-8 hours earlier with frontal passage (Monday early evening vs. early Tuesday morning). But it looks like all the real action may form to our east again.

We may need to watch for some thunderstorm development in Central and N TX as the day wears on. Perhaps just enough instability to fire off some storms to our N that will move close to SE TX as evening approaches.

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0743 AM CDT FRI APR 01 2011

VALID 011300Z - 021200Z

...NO SVR TSTM AREAS FORECAST...

...TX...

SURFACE LOW ANALYZED N OF ABI AS OF 11Z WILL DEVELOP SEWD TOWARD THE
HILL COUNTRY TODAY...GRADUALLY WEAKENING AS IT IS OVERTAKEN BY A
COLD FRONT PROGRESSING SEWD THROUGH THE SRN PLAINS. A MODIFIED CP
AIR MASS --DELINEATED BY PW VALUES OF .75-1.00 INCH AND DEWPOINTS IN
THE LOWER TO MID 60S-- WILL BE ADVECTED NWD IN ADVANCE OF SURFACE
LOW...AND S OF A DIFFUSE WARM FRONT LIFTING INTO THE RED RIVER
VALLEY. THIS MOISTURE IN CONJUNCTION WITH STRONG DIABATIC HEATING
AND CONDITIONALLY UNSTABLE MIDLEVEL LAPSE RATES WILL YIELD A
MODERATELY UNSTABLE WARM SECTOR BY AFTERNOON WITH MLCAPE VALUES
APPROACHING 1000 J/KG.

WHILE SYNOPTIC-SCALE HEIGHT RISES IN THE MIDLEVELS ARE FORECAST
ACROSS THE REGION TODAY...LATEST MESOSCALE MODEL GUIDANCE AND WATER
VAPOR IMAGERY SUGGEST THAT A LOW-AMPLITUDE IMPULSE CURRENTLY MOVING
INTO THE CNTRL HIGH PLAINS COULD GLANCE THE REGION DURING THE PEAK
OF THE DIURNAL HEATING CYCLE. WHEN COUPLED WITH SUSTAINED
CONVERGENCE NEAR THE COLD FRONT-DRYLINE TRIPLE POINT...POTENTIAL
WILL EXIST FOR ISOLATED TO WIDELY SCATTERED TSTM DEVELOPMENT LATE
THIS AFTERNOON INTO EVENING. FORECAST HODOGRAPHS SHOW
VERTICALLY-VEERING WIND PROFILES WITH 40-50 KT OF DEEP NWLY SHEAR...
SUPPORTIVE OF SUSTAINED/ROTATING UPDRAFTS. AS SUCH...THE POTENTIAL
WILL EXIST FOR ISOLATED OCCURRENCES OF SEVERE HAIL AND LOCALLY
DAMAGING WIND GUSTS INTO THIS EVENING.

Some of the meso models as well as the GFS are hinting some thunderstorm development near Austin later this afternoon. We'll see if they are in fact sniffing some activity. HGX thinks College Station could approach the upper 80's.

SPC Update for today:

...N TX THIS AFTERNOON/EVENING...
A WEAK COLD FRONT ACROSS CENTRAL OK AND NW TX WILL DRIFT SEWD INTO N
CENTRAL TX BY THIS EVENING...WHILE LOW-LEVEL MOISTURE RETURN
CONTINUES NWD/NEWD IN ADVANCE OF THE FRONT. REGIONAL 12Z SOUNDINGS
SUGGEST THAT THE MOISTURE WILL BE SUBJECT TO DEEP VERTICAL MIXING AS
SURFACE TEMPERATURES WARM INTO THE 80S...AND UPSTREAM MIDLEVEL LAPSE
RATES ARE NOT PARTICULARLY STEEP. THE NET RESULT WILL BE AFTERNOON
MLCAPE OF 500-1000 J/KG AND INVERTED-V LOW-LEVEL PROFILES...WHICH
WILL SUPPORT HIGH-BASED THUNDERSTORM DEVELOPMENT IN THE ZONE OF
LOW-LEVEL ASCENT ALONG THE FRONT THIS AFTERNOON/EVENING. EFFECTIVE
BULK SHEAR AOA 50 KT WILL FAVOR SUPERCELLS...THOUGH THE LARGE HAIL
THREAT WILL BE TEMPERED SOME BY THE MODEST LAPSE RATES ALOFT.
STRONG DOWNBURST WINDS WILL ALSO BE POSSIBLE GIVEN THE STEEP
LOW-LEVEL LAPSE RATES AND LARGE DEWPOINT DEPRESSIONS NEAR THE
SURFACE. THE SMALL WINDOW OF OPPORTUNITY AND LIMITED MAGNITUDE OF
THE THREAT SUGGEST THAT AN UPGRADE TO SLGT RISK IS NOT CLEARLY
NECESSARY AT THIS TIME.

Updates:

RIGHT NOW IT APPEARS THAT A LINE OF SHOWERS AND POSSIBLY A FEW
THUNDERSTORMS WILL ACCOMPANY THE COLD FRONT. THERE SHOULD BE
AMPLE MOISTURE AS BOTH NAM/GFS BRING 1.7-1.8 INCH PRECIP WATER
OVER THE REGION BY 18Z MON. THIS MOISTURE AXIS THEN SHIFTS EAST
AS THE FRONT PUSHES THROUGH SE TX. INSTABILITY WILL LIKELY BE ON
THE ORDER OF 2500 J/KG AND UPPER LEVEL FLOW WILL BE ENOUGH FOR
ORGANIZED STORM STRUCTURES. THE ENVIRONMENT WILL SUPPORT SEVERE
THUNDERSTORMS EXCEPT FOR A COUPLE OF DETAILS. FIRST THE SE TX
WILL BE ON THE RIGHT SIDE (DESCENDING AIR) OF THE JET STREAK
PUSHING THROUGH THE S PLAINS. THE CAP SHOULD BE SLOW TO ERODE IF
AT ALL GIVEN THE JET STRUCTURE. THE CAP WILL ALSO BE STRONG GIVEN
50 KT LLJ AT 850 MB AND 850 MB TEMPS PUSHING 17-20C. BY THE TIME
JET DYNAMICS BECOME MORE FAVORABLE FOR CONVECTION (00Z-06Z
TUE)...THE FRONT IS EXPECTED TO BE OFF THE COAST. AT THIS
TIME...THINK THAT THE MODELS ERODE THE CAP TOO QUICKLY AND ARE
UNDER DOING THE CAP STRENGTH. THE FORECAST WILL CONTINUE TO
MENTION 30-40 POPS WITH SHOWERS AND ISO THUNDER MENTIONED. IT IS
POSSIBLE THAT THE CAP COULD ERODE SOONER BUT THE UPPER LEVEL
TROUGH AND JET DYNAMICS WILL HAVE TO SHIFT FARTHER SOUTH. GIVEN
MODEL CONSENSUS...DO NOT SEE THIS HAPPENING.

Another interesting event to keep an eye on. Will not dismiss it just yet until the day of in the event forecasts change.

Will be waiting to see the 400 AM update from HGX as well as the Day 3 Update from SPC.

Perhaps a small chance of storm development in Central TX tomorrow night. It does appear we will see a daytime frontal passage on Monday and hopefully some rain as well.

SPC for tomorrow:

...CENTRAL TX...
FARTHER S...THE POTENTIAL WILL EXIST FOR TSTM DEVELOPMENT LATE IN
THE FORECAST PERIOD AS THE COLD FRONT ADVANCES SWD INTO THIS REGION.
MODERATE INSTABILITY AND EFFECTIVE BULK SHEAR 30-40 KT SUGGESTS
ORGANIZED STORMS WILL BE POSSIBLE. UNCERTAINTY IN STORM INITIATION
THIS FAR SOUTH AMONGST THE MODEL SOLUTIONS...AND THE MODELS THAT DO
INITIATE OVER THIS AREA SUGGEST THE TIMING IS AFTER 04/03-06Z.
GIVEN THESE FACTORS...ONLY LOW SEVERE PROBABILITIES /5 PERCENT/ ARE
WARRANTED AT THIS TIME.