December-Wet/Stormy New Years Eve Ahead

[wxman57]

I'd trust the Euro solution over the GFS for next week (unfortunately for me). Front moving through much earlier (Monday) though nothing too extreme as far as temps. Maybe upper 30s at IAH Tue/Wed with highs in the 60s. There is certainly some quite cold air building in western Canada (again, unfortunately for me). I'm afraid it won't stay up there forever.

[JackCruz]

Why must this be so far out?
Absolutely gorgeous! All we need is some precip around that time couple inches

[Katdaddy]

Areas of dense fog along and S of I-10 this morning will create a messy rush hour so please leave early and drive safe. The fog will burn off by mid morning as rain chances increase. Its possible we may see some strong to possibly severe storms this afternoon as a weak front/wind shift moves across the area between noon and 6PM.

[weatherguy425]

http://www.meteo.psu.edu/~fxg1/ECMWF_0z/ecmwfloop.html

Nice change of heart by the ECMWF last night. Hopefully it'll keep it up.

Edit: I thought I was able to upload a saved image into a post? When, wasn't able to figure out how though. Have click and "open image in new tab". Maybe a moderator wouldn't mind fixing it?

[srainhoutx]

The Euro did trend toward the GFS suggesting a deepening trough in the Great Basin over the weekend and that does tend to signal a rather potent Winter Storm developing Sunday through Tuesday affecting the Southern Rockies/Southern Plains with both Winter and Severe elements. More on that later.

The SPC has SE TX/SW LA outline for isolated severe potential later this afternoon/tonight as a short wave and attented Pacific front sag into Central/SE/E TX/Western Louisiana.

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0651 AM CST TUE DEC 04 2012

VALID 041300Z - 051200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
MORNING WATER VAPOR DATA INDICATE A MID-LEVEL CYCLONE OVER NRN
ONTARIO THAT IS PROJECTED TO TRACK NEWD INTO QUEBEC. THIS FEATURE IS
ACCOMPANIED BY A SHORTWAVE TROUGH THAT WILL MOVE ACROSS THE UPPER
MIDWEST AND GREAT LAKES BEFORE EVENTUALLY REACHING THE NERN STATES
BY EARLY WED MORNING. A SEPARATE SRN SHORTWAVE TROUGH WILL PROGRESS
ESEWD ACROSS THE SRN PLAINS...LOWER MS VALLEY...AND NRN GULF. A SFC
FRONT ASSOCIATED WITH THE COMPOSITE ERN/S-CNTRL-CONUS SHORTWAVE
TROUGHS WILL CONTINUE TO ADVANCE EWD/SWD THROUGH TONIGHT...AND
EXTEND FROM COASTAL NEW ENGLAND TO THE LOWER MS VALLEY TO THE NW
GULF BY EARLY WED MORNING.

...PORTIONS OF ERN/SRN TX...NRN/WRN LA...SRN AR...WRN MS THIS
AFTERNOON AND THIS EVENING...
ONGOING CONVECTION INVOF THE FRONT OVER NRN AR WILL LIKELY BE
STEERED ACROSS THE MID-SOUTH WHERE LOW-LEVEL MOISTURE/INSTABILITY
WILL BE RELATIVELY SMALLER IN MAGNITUDE COMPARED TO LOCATIONS
FARTHER SOUTH. THROUGH MID-DAY...ADDITIONAL STORMS WILL LIKELY
DEVELOP ACROSS THE LOWER MS VALLEY OVER THE SRN FLANKS OF THE
ONGOING CONVECTION...AND WITHIN A ZONE OF WEAK LOW-LEVEL
WAA/CONFLUENCE THAT LEADS THE FRONT. THIS AFTERNOON...STRONGER
STORMS WILL LIKELY DEVELOP ALONG THE FRONT FROM SRN AR INTO SRN TX.
THIS WILL OCCURS AS DIURNAL HEATING COMBINES WITH MODESTLY STEEP
MID-LEVEL LAPSE RATES OVERSPREADING PREFRONTAL DEWPOINTS IN THE
LOWER AND MIDDLE 60S. FORECAST SOUNDINGS SUGGEST THAT 500-1500 J/KG
OF MLCAPE WILL BE COMMON ACROSS THE AREA.

WITH 20-30 KT OF 500-MB FLOW...DEEP SHEAR IS NOT EXPECTED TO BE
STRONG...WITH CLUSTERS OF MULTICELL STORMS LIKELY BEING THE
PREDOMINANT CONVECTIVE MODE. ISOLATED INSTANCES OF SVR WINDS/HAIL
WILL BE POSSIBLE WITH THE MOST INTENSE STORMS. WEAK LOW-LEVEL FLOW
WILL ALSO PREVENT A MORE SUBSTANTIAL SVR THREAT FROM EVOLVING.

STORMS WILL LIKELY BE MOVING OFF THE TX COAST DURING THE EVENING
HOURS...WITH STORMS ACROSS THE LOWER MS VALLEY MOVING EWD/SEWD WHILE
WEAKENING DURING THE MID/LATE EVENING.

..COHEN/CORFIDI.. 12/04/2012

[srainhoutx]

Nice change of heart by the ECMWF last night. Hopefully it'll keep it up.





Edit: I thought I was able to upload a saved image into a post? When, wasn't able to figure out how though. Have click and "open image in new tab". Maybe a moderator wouldn't mind fixing it?

You have to save individual images and upload them weatherguy425. Unfortunately loops of guidance won't unload. That said as you mentioned the 00Z Euro did trend toward what the GFS had been suggesting for the past 4 days with a deepening Great Basin trough as well as a robust upper low closing off at the base of that trough. There are hints of both Winter and Severe elements that could be involved with this potential negative tilted trough axis. We need to see a bit more agreement in the guidance before biting too hard on any solution. The guidance has been all over the place regarding the piece of colder air and the 500mb pattern. That said it does raise an eyebrow because it has been a very long time since we've seen such a scenario develop this far S and we'll need to see a bit more continuity before honing in on a final solution 6-8 days out. It is encouraging though and does suggest the long awaited pattern change may well be in the cards. We will see.

00Z Euro:

00Z GFS:

[srainhoutx]

Morning e-mail from Jeff:

A chance for strong thunderstorms this afternoon.

Warm and muggy air mass that has been in place since late last week will be lifted by an incoming frontal boundary this afternoon. Radar currently shows showers along and east of a moisture plume off the SE TX coast extending from near Sabine Pass to offshore of High Island. This plume of deeper moisture has been very slowly working its way WNW over the last 24 hours and should spread inland along and south of US 59 today. Expect scattered showers to develop along the coast and begin to move inland over the next few hours as the dense fog burns off and surface heating starts to bubble up the low levels.

Weak cool front over NW TX will move SE today and enter our NW counties by late morning and sweep off the coast by early evening. Lift along the front will combine with an increasingly unstable air mass and increasing moisture to produce a showers and thunderstorms along and ahead of this boundary. Meso scale models are in good agreement on widespread development around noon from College Station to Lufkin which spreads SE this afternoon across most of the area. Parameters are in place for a few strong storms, but the severe threat is on the low side with weak shear. Once again this looks like a fairly decent shot at rainfall, but given the lack of rainfall with the past few events I am somewhat hesitant that widespread wetting rains will actually occur. With that said, feel that most areas will see some rainfall with the greatest amounts along and SE of US 59.

Cooling behind this front will be weak and short lived as the fast progressive pattern remains in place across the US. Instead of the record heat from the weekend highs will fall back toward the mid 70’s on Wednesday and Thursday with lows in the 50’s, both of which remain above early December averages. Weak boundary retreats northward on Thursday and this will return well above average temperatures and humidity to the region this weekend. Highs will return to the toasty 80’s by Saturday under southerly Gulf flow…but significant changes will follow.

Long Range:
After weeks warmth…some record…across much of the nation, the upper air pattern looks to finally break down from its fast progressive west to east flow to more amplification of a ridge of high pressure off the western US coast. This newly developing upper air pattern will shut off the parade of storm system into the W coast and direct the development of a downstream trough over the western US and plains. Cold air which has been bottled up in NW Canada will be unleashed into the US by this weekend and spread rapidly down the plains and into TX by early next week. Long range global models are having a hard time resolving the timing of this strong old front and how cold the post frontal air mass might be. Given past history with shallow cold air masses, will take the faster and colder solutions and expect a strong front to push into SE TX sometime early Monday and sweep off the coast during the day. Highs will be prior to the front with rapidly falling temperatures behind the boundary into the 40’s and 50’s under strong cold air advection. Some degree of energy does look to lag back in the base of the trough over the SW US post front which may keep clouds around behind the front and temper the temperature rise during the day. Still plenty of time to fine tune the affects of this pattern change and eventual air mass change…but finally some longer lasting cold air looks to be headed this way.

[wxman57]

06Z GFS jumped way faster than the 00Z Euro with next Monday's front. Euro moves it through around 2pm Monday, 6Z GFS has it through before sunrise. The 00Z GFS moved it through 24 hrs later. Euro's post-frontal temps here in the mid to upper 40s Tue and low 40s Wed. Nothing extreme indicated (i.e., near freezing). However, the Euro has highs in the mid 50s here Tue and mid to upper 50s Wed.

P.S. I don't like the last line of Jeff's email...

[srainhoutx]

The 12Z NAM (WRF/NMM), GFS and the SREF ensembles at 09Z suggest a Slight Risk from the SPC could be introduced for portions of SE TX/SW LA later today. We will see.

[wxman666]

Slight risk of severe from the middle TX coast to South TX Includes parts of the viewing area.

SPC AC 041611

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1011 AM CST TUE DEC 04 2012

VALID 041630Z - 051200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MIDDLE TX COAST INTO
PARTS OF DEEP S TX...

...SYNOPSIS...

THE PRIMARY FEATURE OF INTEREST THIS PERIOD IS A LOW-LATITUDE
SHORTWAVE TROUGH WHICH WILL TRANSLATE SEWD FROM THE OZARK PLATEAU
AND SRN PLAINS INTO THE LOWER MS VALLEY AND NRN GULF OF MEXICO.
EMBEDDED WITHIN THIS BROADER-SCALE FEATURE...A VORTICITY MAXIMUM
OVER ERN OK AS OF MID MORNING WILL WEAKEN TODAY IN RESPONSE TO THE
SEWD PROGRESSION AND AMPLIFICATION OF A SECONDARY VORTICITY MAXIMUM
AND ASSOCIATED MIDLEVEL JET STREAK FROM WRN TX INTO THE NWRN GULF OF
MEXICO. MEANWHILE...AN ACCOMPANYING SURFACE COLD FRONT ANALYZED
FROM NEAR THE CONFLUENCE OF THE MS AND OH RIVERS SWWD INTO THE TX
HILL COUNTRY AS OF 15Z WILL CONTINUE SEWD TOWARD THE TX COAST AND
INTO THE LOWER MS VALLEY...SERVING AS THE FOCUS FOR TSTM
DEVELOPMENT.

...MIDDLE TX COAST INTO DEEP S TX THIS AFTERNOON AND EVENING...

12Z REGIONAL SOUNDINGS SHOWED THE PRESENCE OF A MOIST AIR MASS /I.E.
LOWEST 100-MB MEAN-MIXING RATIOS OF 12-14 G PER KG/ BENEATH MODESTLY
STEEP MIDLEVEL LAPSE RATES OF AROUND 7 C/KM. WHEN COMBINED WITH
LOCAL CLOUD BREAKS...THE POTENTIAL WILL EXIST FOR CORRIDORS OF
MODERATE AFTERNOON INSTABILITY WITH MLCAPE VALUES APPROACHING
1000-2000 J/KG. LOW-LEVEL UPLIFT ALONG THE COLD FRONT AND
DEVELOPING SEA-BREEZE WILL COMBINE WITH INCREASING HEIGHT FALLS/DCVA
ATTENDANT TO W TX VORTICITY MAXIMUM TO FOSTER WIDELY SCATTERED TO
SCATTERED TSTMS BY MID/LATE AFTERNOON. THE SEWD PROGRESSION OF THE
MIDLEVEL JET STREAK ATTENDING THE VORTICITY MAXIMUM WILL LEAD TO A
CORRESPONDING INCREASE IN VERTICAL SHEAR WITH THE KINEMATIC
ENVIRONMENT BECOMING SUPPORTIVE OF SUPERCELLS AND ORGANIZED LINE
SEGMENTS WITH AN ASSOCIATED RISK FOR DAMAGING WINDS AND LARGE HAIL
THROUGH THIS EVENING.

[Katdaddy]

SPC now has a slight risk for the SW areas down the coast for today.

[srainhoutx]

Radars are beginning to light up across the Region:

[srainhoutx]

MESOSCALE DISCUSSION 2130
NWS STORM PREDICTION CENTER NORMAN OK
1109 AM CST TUE DEC 04 2012

AREAS AFFECTED...SERN TX...WRN-NERN LA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 041709Z - 041845Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...SCATTERED THUNDERSTORM COVERAGE APPEARS LIKELY DURING THE
AFTERNOON FROM SERN TX INTO WRN-NERN LA. ISOLATED THREAT FOR
MARGINALLY SEVERE HAIL AND DAMAGING WIND GUSTS WILL EXIST.
HOWEVER...A WW DOES NOT APPEAR NECESSARY.

DISCUSSION...MIDDAY MESOANALYSIS SHOWS A COLD FRONT EXTENDING S-SWWD
FROM THE ARKLATEX REGION INTO SRN TX. ASCENT SPREADING EWD AHEAD OF
A SHORTWAVE TROUGH LOCATED OVER W TX IS AIDING IN THUNDERSTORM
DEVELOPMENT ALONG THE FRONT IN E-CNTRL TX. AHEAD OF THE FRONT FROM
SERN TX INTO NERN LA...PARTIAL CLEARING HAS ALLOWED TEMPERATURES TO
WARM INTO THE 70S...WHILE DEWPOINTS RESIDE IN THE UPPER 60S. GIVEN
THE PRESENCE OF MIDLEVEL LAPSE RATES FROM 6.5-7.0 C/KM...MODIFIED
12Z RAOBS YIELD MLCAPE VALUES FROM 1000-2000 J/KG. THIS
THERMODYNAMIC ENVIRONMENT COMBINED WITH A CONFLUENT SURFACE FLOW
REGIME WILL FAVOR SCATTERED STORM COVERAGE ALONG AND AHEAD OF THE
FRONT DURING THE AFTERNOON. PRIMARY LIMITING FACTOR FOR GREATER
SEVERE WEATHER POTENTIAL IS WEAK DEEP-LAYER WIND SPEEDS AND SHEAR.
HOWEVER...MODERATE INSTABILITY WITHIN THE AREA OF PARTIAL CLEARING
MAY ALLOW A FEW MULTICELL THUNDERSTORMS TO PULSE UPWARDS IN
INTENSITY AND POSE A THREAT FOR MARGINALLY SEVERE HAIL AND
STRONG/SEVERE WIND GUSTS.

..GARNER/MEAD.. 12/04/2012


ATTN...WFO...JAN...LCH...SHV...HGX...

[MontgomeryCoWx]

Pouring Rain at my place in Conroe.

[Katdaddy]

SEVERE THUNDERSTORM WARNING
TXC225-313-455-471-041800-
/O.NEW.KHGX.SV.W.0164.121204T1724Z-121204T1800Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1124 AM CST TUE DEC 4 2012

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
SOUTHWESTERN HOUSTON COUNTY IN SOUTHEAST TEXAS...
EASTERN MADISON COUNTY IN SOUTHEAST TEXAS...
SOUTHWESTERN TRINITY COUNTY IN SOUTHEAST TEXAS...
EXTREME NORTHERN WALKER COUNTY IN SOUTHEAST TEXAS...

* UNTIL 1200 PM CST

* AT 1122 AM CST...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM
CAPABLE OF PRODUCING QUARTER SIZE HAIL AND DAMAGING WINDS IN
EXCESS OF 60 MPH. THIS STORM WAS LOCATED 15 MILES WEST OF
TRINITY...OR 16 MILES EAST OF MADISONVILLE...AND MOVING EAST AT 40
MPH.

* LOCATIONS IMPACTED INCLUDE...
TRINITY...LOVELADY AND MIDWAY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS IN EXCESS OF 60 MPH...
DESTRUCTIVE HAIL...DEADLY LIGHTNING AND VERY HEAVY RAIN. FOR YOUR
PROTECTION...MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR
HOME OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE
INTO AREAS WHERE WATER COVERS THE ROAD.

[srainhoutx]

Looking ahead to the upcoming weekend/early next week, the 12Z Euro is suggesting a significant Winter Storm dropping S into the Great Basin that brings a robust upper air disturbance (short wave) that would suggest heavy snow into most of New Mexico/Colorado/TX Panhandle/Oklahoma and possibly even portions of N TX. There does appear to be the potential for severe weather further S as the strong cold front passes Central/South/SE Texas as well on Monday.

[srainhoutx]

MESOSCALE DISCUSSION 2131
NWS STORM PREDICTION CENTER NORMAN OK
0108 PM CST TUE DEC 04 2012

AREAS AFFECTED...TX COASTAL PLAIN

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 041908Z - 042115Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...A SMALL SEVERE TSTM WATCH MAY BE CONSIDERED FOR PARTS OF
THE TX COASTAL PLAIN THIS AFTERNOON-EVENING. ISOLD LARGE HAIL AND A
FEW INSTANCES OF STRONG-SEVERE WIND GUSTS ARE POSSIBLE THRU THE
EARLY EVENING.

DISCUSSION...TRENDS IN VISIBLE SATELLITE IMAGERY SHOW A SWELLING CU
FIELD INVOF A PRE-FRONTAL WINDSHIFT AND OVER A WARM SECTOR LOCATED
OVER THE TX COASTAL PLAIN. SURFACE TEMPS HAVE WARMED INTO THE LOWER
80S AMIDST AN ADEQUATELY MOIST/DESTABILIZING AIRMASS. A MID-LEVEL
SPEED MAX IS CONTINUING TO APPROACH THE REGION FROM THE CONCHO RIVER
VALLEY/EDWARDS PLATEAU REGION. UPWARD VERTICAL MOTION ASSOCIATED
WITH THE UPPER FEATURE...COMBINED WITH WEAK LOW LEVEL CONFLUENCE
ALONG THE PREFRONTAL BOUNDARY...AND DIABATIC HEATING WILL ACT TO
FURTHER WEAKEN THE CAP SAMPLED BY THE 12Z CRP RAOB. THE CAP HAS
ALREADY ERODED FROM MATAGORDA BAY NEWD TO THE SABINE RIVER...WITH
SCTD STORMS /OCCASIONAL PULSATING SEVERE UPDRAFT/ EXPECTED TO LEAD
TO SUBSTANTIAL CONVECTIVE OVERTURNING OVER THE NEXT FEW
HRS...THEREBY LESSENING THE SEVERE RISK IN THIS REGION. FARTHER
SSW...MORE SPARSE CONVECTIVE COVERAGE --LIKELY DELAYED UNTIL
MID-LATE AFTERNOON-- IS EXPECTED. UPWARDS OF 40 KT DEEP SHEAR AND A
MODERATELY UNSTABLE AIRMASS /1500 J/KG MLCAPE/ WILL SUPPORT
ORGANIZED STORM STRUCTURES CAPABLE OF ISOLD LARGE HAIL/DMGG WIND
GUSTS.

..SMITH/MEAD.. 12/04/2012


ATTN...WFO...HGX...CRP...EWX...BRO...

[srainhoutx]

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
135 PM CST TUE DEC 4 2012

TXZ177>179-198>200-042030-
WALKER TX-MONTGOMERY TX-LIBERTY TX-SAN JANCINTO TX-POLK TX-GRIMES TX-
135 PM CST TUE DEC 4 2012

...SPECIAL WEATHER STATEMENT...

AT 131 PM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
A LINE OF STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM
LIVINGSTON TO 11 MILES NORTH OF MAGNOLIA MOVING EAST AT 20 MPH.

HAIL UP TO THE SIZE OF PEAS AND WIND GUSTS UP TO 30 MPH WILL BE
POSSIBLE WITH THESE STORMS.

LOCATIONS IMPACTED INCLUDE...
CLEVELAND...LIVINGSTON...WILLIS...PANORAMA VILLAGE...SHEPHERD...CUT
AND SHOOT...COLDSPRING...MONTGOMERY...NORTH CLEVELAND AND GOODRICH.

[txflagwaver]

Rained earlier...no wind or ran now but frequent lightning. Friend in Rosharon getting hammered

[srainhoutx]

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
243 PM CST TUE DEC 4 2012

TXZ197-210-211-042130-
AUSTIN TX-COLORADO TX-WASHINGTON TX-
243 PM CST TUE DEC 4 2012

...SPECIAL WEATHER STATEMENT...

AT 240 PM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
A STRONG THUNDERSTORM 12 MILES NORTHEAST OF FAYETTEVILLE...OR 13
MILES SOUTHWEST OF BRENHAM...MOVING EAST AT 20 MPH.

HAIL UP TO THE SIZE OF PEAS AND WIND GUSTS UP TO 30 MPH WILL BE
POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
BELLVILLE.