February: Calm Weather To End The Month

[srainhoutx]

From Nesdis...

SATELLITE PRECIPITATION ESTIMATES..DATE/TIME 02/15/12 2159Z
SATELLITE ANALYSIS BRANCH/NESDIS---NPPU---TEL.301-763-8678
LATEST DATA USED: GOES-13 2145Z JBN
.
LOCATION...MISSISSIPPI...LOUISIANA...ARKANSAS...TEXAS...
.
ATTN WFOS...JAN...LIX...LCH...SHV...HGX...
ATTN RFCS...LMRFC...WGRFC...
.
EVENT...CONVECTION MOVING ACROSS SE TX/LA
.
SATELLITE ANALYSIS AND TRENDS...LATEST GOES IR/VIS IMAGERY CONTINUES
TO SHOW AN AREA OF CONVECTION EXTENDING FROM CNTRL/NRN LA WSW INTO SE
TX. IR IMAGERY SHOWS SOME COOLING/EXPANDING CLOUD TOPS, BUT DIFFICULT
TO DETERMINE HOW MUCH AS THE TOPS OF THE CONVECTIVE CELLS AREA RAPIDLY
BEING SHEARED NEWD BUY 140 KT+ SATELLITE DERIVED JET EXTENDING ACROSS
THE DEEP S. VIS IMAGERY DOES A MUCH BETTER JOB DEPICTING THE INTENSITY
OF THE CONVECTION AND DOES SHOW SEVERAL SMALL OVERSHOOTING TOPS POKING
THROUGH THE SHEARED CIRRUS CLOUDS. THIS SUGGESTS THAT THE CONVECTION HAS
INTENSIFIED SOME THE PAST 2-3 HRS AS THERE WERE NO OVERSHOOTING TOPS
SEEN PER THE PREVIOUS IMAGE. IN ADDITION, VIS IMAGERY ALSO SHOWS THAT
CONVECTION CONTINUES TO BACK BUILD ON THE TAIL END OF THE LINE OVER
SE TX WHICH IS HELPING TO SLOW THE LINE DOWN AND IS ALLOWING FOR SOME
TRAINING TO OCCUR. SFC OBS FROM ACROSS SE TX SUGGEST RAIN RATES ARE
IN THE 1-2"/HR RANGE WITH THE CONVECTION WITH A FEW AREAS PICKING UP
1-2" OF RAIN THE PAST 3 HRS. SIMILAR AMOUNTS AND RATES CAN BE EXPECTED
ACROSS THE DISCUSSION AREA THE NEXT 2-3 HRS AS THE CONVECTION MOVES
ENEWD ACROSS TX/LA.
.
SHORT TERM OUTLOOK VALID 22Z-01Z...MEDIUM TO HIGH CONFIDENCE FACTOR
IN SHORT
TERM OUTLOOK...THE POTENTIAL EXISTS FOR SOME ISOLATED FLASH FLOODING
THE NEXT FEW HRS ACROSS SE TX/LA AS SOME TRAINING IS POSSIBLE WITH THE
ONGOING CONVECTION. THE CLUSTER SOULD CONTINUE ON ITS NE/ENEWD TRACK
ACROSS THE REGION WITH SOME BACK BUILDING CONTINUING ON THE TAIL END OVER
SE TX THE NEXT FEW HRS. THIS SHOULD CONTINUE TO ALLOW FOR ADDITIONAL
RAIN FALL AMTS OF 1-2" IN A FEW AREAS THE NEXT 2-3 HRS AND COULD LEAD
TO ISOLATED FLASH FLOODING CONCERNS ACROSS THE DISCUSSION AREA.

[mckinne63]

niner21, I appreciate your rant but it will be a cold day in hell before I ever wish for rain to go away.

I hear you redneckweather! After last summer, I will not complain about rain again. This has been a glorious January/February. The yard is soggy and the mulch will just have to wait. I will take the rain when we can get it.

[jasons2k]

I measured .95" today and .31" earlier this week.

[ticka1]

niner21, I appreciate your rant but it will be a cold day in hell before I ever wish for rain to go away.

I hear you redneckweather! After last summer, I will not complain about rain again. This has been a glorious January/February. The yard is soggy and the mulch will just have to wait. I will take the rain when we can get it.

I agree - the rain is an answer to my prayers since last April when the drought got serious. This rain will keep alot of businesses in business like water recreation, campgrounds and boating with the lakes adding to their levels. I am going to keep praying for more rain - every few days. This is what is getting us out of our drought.

[Ptarmigan]

niner21, I appreciate your rant but it will be a cold day in hell before I ever wish for rain to go away.

I hear you redneckweather! After last summer, I will not complain about rain again. This has been a glorious January/February. The yard is soggy and the mulch will just have to wait. I will take the rain when we can get it.

I don't want another drought. I will take the rain.

[biffb816]

I don't want another drought.

Me either, but I'ld be totally cool with spreading all this rain out a little.

[srainhoutx]

The overnight models have come into much better agreement with Friday/Saturday time frame and it now appears a wide spread flood potential exists and the threat of severe storms also increases. The guidance has shifted the very heavy rainfall potential further inland and an area wide Flash Flood Watch may be needed for the first time since September 2010. 2-4 inches of rain appear possible across the entire region with some possible 5-6+ inch amounts not out of the question should slow moving severe storms with training develop. The exact focus of where the heavy rainfall cannot be known at this time, but with a slow moving Coastal Low and a potent upper level trough/low trekking E from old Mexico along or just N of the I-10 corridor areas from Central and SE TX appear to be the bulls eye for significant weather and extremely heavy rainfall. Our air mass is very moist and primed for such an event and I urge everyone to follow the forecasts and updates closely the next 24 hours as severe weather chances may be introduced and Flash Flood Watches may be hoisted across our entire region.

[srainhoutx]

Morning e-mail from Jeff:

Heavy to excessive rainfall becoming likely over the region Friday-Saturday

Flash Flood Watches may be required

Very weak cool front trying to limp through the area this morning with dense fog south and east of the boundary. Strong sub-tropical jet stream aloft riding nearly parallel to this boundary is already helping to set off an area of widespread thunderstorms over S TX and the adjacent western Gulf waters. Moisture will be on a rapid increase today as ESE to SE winds above the surface begin to bring Gulf moisture back inland over the frontal slope. TX Tech meso model breaks out showers/thunderstorms across the counties counties by this evening in a region of enhanced lift from an approaching upper air disturbance and increasing isentropic lift over the coastal waters frontal boundary.

Will likely see a break in the action early Friday before the onset of the main event Friday afternoon-Saturday morning. Strong upper level trough over S CA this morning will dig SE into MX and then eject across TX early Saturday. This system will force a western Gulf of Mexico surface low with strong isentropic upglide over much of the southern half of TX by midday Friday. Expect widespread rains to quickly develop and spread NE during the day on Friday. NW Gulf surface boundary begins to back northward in response to NW Gulf surface low formation and this will add a surface boundary into the mix to help focus training of heavy rainfall. Current thinking is that this boundary will not move very far inland if at all and the threat for the really big totals may be out over the Gulf water however should this boundary move further north than expected, rainfall totals will need to be raised and the flash flood threat will be even higher. Even with the surface boundary remaining near the coast/offshore, there will be very strong lift coming to bear across the region along with the 850mb boundary in the region and both of these will favor some form of heavy rainfall inland. Could also see some strong elevated thunderstorms Friday night with the main threat being hail. System should clear the area by Saturday evening with another 24-36 hour break before the next system arrives Monday-Tuesday.

Rainfall Amounts/Hydro:
Upstream look at PW values shows a deep pool of 1.6-1.7 inch values over deep S TX into N MX and this moisture will rapidly spread northward over the next 24 hours. These moisture levels will be at or above the 200% levels for this time of year and when combined with some kind of stalled or slow moving boundary (surface front or 850mb front) really raises the warning flags when it comes to excessive rainfall and flooding. Additionally rainfall in the past 3 weeks has been well above average and frequent with little drying of the soil moisture between events. The top layers of soil are now saturated and will result in quicker run-off. Our northern counties are wetter than the coastal and SW counties as this has been where the greatest rainfall has been over the past month and this event looks to focus in the coastal areas.

Will go with widespread 1-3 inches of rainfall south of I-10 with isolated amounts of 4-5 inches possible especially under the strongest storms and where training develops. Locations most at risk for some of the heavier totals appear to be right along the coast northward to US 59 near/just north of the surface front and south of the 850mb front. North of I-10 totals will average .5-2.0 inches.

With grounds saturated or nearing saturation rainfall of this magnitude will result in large amounts of run-off. Significant rises on area creeks, bayous, and rivers will be likely if the rainfall forecast verify as forecasted.

HPC (Day 1-3 rainfall (QPF) Totals)

[srainhoutx]

SHORT RANGE FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
239 AM EST THU FEB 16 2012

VALID 12Z THU FEB 16 2012 - 12Z SAT FEB 18 2012

...RAIN AND SNOW TO AFFECT PORTIONS OF THE EASTERN STATES TODAY
INTO FRIDAY...

...LOW PRESSURE IS EXPECTED TO DEVELOP AND DEEPEN ALONG THE
WESTERN GULF COAST BY EARLY SATURDAY SPREADING NUMEROUS SHOWERS
AND THUNDERSTORMS ACROSS THE GULF COAST...

AN UPPER-LEVEL DISTURBANCE WILL MOVE ACROSS THE GREAT LAKES REGION
TODAY...WITH AN ASSOCIATED SURFACE FRONTAL SYSTEM EXPECTED TO
SPREAD PRECIPITATION ACROSS MUCH OF THE EASTERN STATES. SHOWERS
AND THUNDERSTORMS WILL BE POSSIBLE ACROSS THE SOUTHERN STATES.
FARTHER NORTH...ACROSS THE CENTRAL APPALACHIANS AND MID-ATLANTIC
REGION...THE SYSTEM WILL HAVE ACCESS TO SOMEWHAT LESS
MOISTURE...THEREFORE SCATTERED SHOWERS ARE EXPECTED. FARTHER
NORTH...AND CLOSER TO THE UPPER-LEVEL DYNAMICS...PRECIPITATION
WILL BE MORE WIDESPREAD...WITH RAIN AND SNOW POSSIBLE FOR AREAS
FROM THE GREAT LAKES EASTWARD INTO INLAND NEW ENGLAND.
PRECIPITATION WILL REACH THE NEW ENGLAND COASTLINE BY THIS EVENING.

A WEAK SYSTEM WILL IMPACT THE PACIFIC NORTHWEST TODAY...SPREADING
SCATTERED RAIN AND SNOW SHOWERS INTO THE REGION. ANOTHER
STRONGER...AND DEEPER STORM SYSTEM WILL APPROACH THE PACIFIC
NORTHWEST LATE ON FRIDAY...BRINGING MORE WIDESPREAD PRECIPITATION
TO THE REGION.

FINALLY...A VIGOROUS DISTURBANCE IN THE SUBTROPICAL JET STREAM IS
DIGGING ACROSS SOUTHERN CALIFORNIA EARLY THIS MORNING...AND IS
FORECAST TO MOVE SOUTHEASTWARD INTO NORTH CENTRAL MEXICO BY LATE
FRIDAY. AS THIS SYSTEM INTERACTS WITH A STATIONARY FRONTAL
BOUNDARY DRAPED FROM NORTHERN MEXICO EASTWARD ALONG THE GULF
COAST...A WAVE OF LOW PRESSURE IS EXPECTED TO DEVELOP ACROSS THE
NORTHWESTERN GULF BY SATURDAY MORNING. THIS SYSTEM WILL BE A
SIGNIFICANT PRECIPITATION PRODUCER FOR MUCH OF THE EASTERN STATES.
BY FRIDAY NIGHT INTO SATURDAY...SHOWERS AND THUNDERSTORMS ARE
FORECAST DEVELOP ACROSS THE WESTERN GULF COAST STATES...WITH SOME
POTENTIAL FOR LOCALLY HEAVY RAINFALL AMOUNTS.

[srainhoutx]

We'll need to monitor South Central Texas overnight. The 12Z WRF/NMM as well as other guidance has been 'sniffing' storms developing in that area along the stalled surface boundary as an upper level vort max swings across the region ahead of the larger upper low to our W and before the Coastal low develops near Corpus during the Friday afternoon/evening time frame. There is some potential of heavy rains/storms with a possible MCS developing overnight into the morning hours on Friday heading in our direction. We will see...

[MontgomeryCoWx]

South Texas needs this really bad! Glad to see it firing up over there.

[srainhoutx]

The 12Z WRF/NMM also suggests very heavy rainfall and storms developing across Central Texas Friday night spreading E with over running conditions well established across Coastal Texas and a Coastal Low developing near Corpus...

[redneckweather]

I will take a good flooding event across the area. Bring it. I don't mean to get ahead of ourselves but what kind of system are we looking at the beginning of next week?

[srainhoutx]

The 12Z GFS tends to agree with the 'theme' of a possible MCS developing near S Central Texas overnight. That model also suggests heavy rainfall N of the Coastal Low with convection and possible training storms along the boundary Friday night into Saturday. I suspect we'll see HGX issue Flash Flood Watches before the day is out.

[Portastorm]

Same with EWX ...

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1037 AM CST THU FEB 16 2012

.UPDATE...
CONVECTION ALONG THE RIO GRANDE IS INCREASING AND MOVING TO THE
NORTH AND NORTHEAST IN RESPONSE TO A DISTURBANCE IN THE SW FLOW
ALOFT. CHANGES TO THE FIRST PERIOD OF THE FCST INCLUDE INCREASING
POPS AND CLOUD COVER WHILE ALSO ADDING THUNDER AND LOWERING
AFTERNOON HIGHS A COUPLE OF DEGREES. THE NEXT 48HRS WILL BE WET
ACROSS SOUTH CENTRAL TEXAS. A FLASH FLOOD WATCH WILL LIKELY BE
ISSUED FRIDAY MORNING FOR PORTIONS OF THE CWFA.

[srainhoutx]

So if HGX is waiting on the Canadian/Euro to agree with what the other guidance has suggested, Flash Flood Watches should be forthcoming...

[srainhoutx]

I will take a good flooding event across the area. Bring it. I don't mean to get ahead of ourselves but what kind of system are we looking at the beginning of next week?

The HPC has interest yet again in what is going on across the Northern Pacific. Winter RECON has been tasked...these include the G-IV high altitude sampling as well as C-130 aircraft...

NOUS42 KNHC 161700
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1200 PM EST THU 16 FEBRUARY 2012
SUBJECT: WINTER STORM PLAN OF THE DAY (WSPOD)
VALID 17/1100Z TO 18/1100Z FEBRUARY 2012
WSPOD NUMBER.....11-079

I. ATLANTIC REQUIREMENTS
1. FLIGHT ONE - TEAL 76 -
A. A-66/ DROP 9 (28.2N 93.9W)/ 18/1200Z
B. AFXXX 02WSA TRACK66
C. 18/0730Z
D. 10 DROPS ON TRACK AS PUBLISHED
E. AS HIGH AS POSSIBLE/ 18/1400Z.

2. OUTLOOK FOR SUCCEEDING DAY: PSBL TRACK 62, FOR BOTH
19/0000Z AND 19/1200Z, CP- (31.3N 75.9W), FLOWN (CW).

II. PACIFIC REQUIREMENTS
1. FLIGHT ONE - NOAA49 -
A. P-54/ DROP 10 (45.0N 166.0W) 18/0000Z
B. NOAA9 21WSC TRACK54
C. 17/1930Z
D. 17 DROPS ON TRACK AS PUBLISHED
E. 41,000 TO 45,000 FT/ 18/0600Z

2. SUCCEEDING DAY OUTLOOK: PSBL ANOTHER TRACK P-54
FOR 19/0000Z/ 45.0N 166.0W.

[harpman]

We are looking at a very nasty Saturday here in the New Orleans area. Parades will be cancelled, etc. Glad to see you guys in Tx are finally getting some drought relief!

By the way, is cold air still forecast to come down to the Gulf coast at the end of the month?? Just curious. thanks.

[srainhoutx]

Actually Ed, the Atlantic mission is for the EC threat. The G-IV and possible C-130 mission is for the early next week system out over the Pacific.

[srainhoutx]

Afternoon e-mail from Jeff:

Flash Flood Watch will be issued from midnight tonight through noon Friday.

Models progging a strong southern stream short wave to cross the area tonight into early Friday ahead of a larger upper level trough/low on Friday night/Saturday. The result is the rapid formation of widespread rainfall and thunderstorm tonight/early Friday across the region as mid level flow backs to the ESE and pumps tremendous Gulf moisture over the top of the stalled front off the coast. Concern is growing that training of excessive rainfall on top of saturated grounds may lead to flooding problems. Additionally, moisture levels will increase to 200% of normal which raises several red flags when dealing with either slow moving or training convection.

Widespread rainfall amounts of .5 to 1.5 inches appear likely by noon of Friday with some isolated totals upwards of 2-3 inches. Flash Flood Guidance for much of the region in the 3 hour time period is on the order of 2.5-3.5 inches with 1 hour guidance of 2.25 to 2.5 inches. Exceedance of these values for their time periods will generate excessive amounts of run-off and likely cause flooding.

Significant rises on area creeks, bayous, and rivers is becoming increasing likely with the forecast rainfall amounts.

Additional heavy rainfall is likely Friday night into Saturday which will only aggravate any ongoing run-off/flooding problems from tonight into Friday morning. May need to bump up total storm rainfall amounts as it is starting to appear the higher end totals may be more in line with what happens.