Possible NW Gulf Development Late This Week?

[lrak]

Late nite radar loops. I'm thinking I see spin, but I think its time to go to bed.

[HouTXmetro]

Rainfall looks impressive down by Corpus. looks like a spin to me too.

[Nederlander]

Not Impressed at all... I am guessing more showers and tstorms will pop up in the morning?? I was really looking forward to the downpour...

[attallaman]

Although I have not been experiencing any lightning or thunder during the night the rain continues to move into my area from the GOM. The weather radar image is courtesy of WWL TV4.COM, NOLA.

http://www.wwltv.com/weather/myownradar ... index.html

[HURAKAN]

813
ABNT20 KNHC 121145
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT SAT SEP 12 2009

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON WEAKENING
TROPICAL STORM FRED...LOCATED ABOUT 645 MILES WEST-NORTHWEST OF THE
CAPE VERDE ISLANDS.

A LARGE AREA OF DISTURBED WEATHER COVERING MUCH OF THE NORTHERN AND
WESTERN GULF OF MEXICO AND ADJACENT LAND AREAS IS ASSOCIATED WITH A
SURFACE TROUGH AND A MID- TO UPPER-LEVEL LOW. ENVIRONMENTAL
CONDITIONS ARE NOT CONDUCIVE FOR TROPICAL CYCLONE DEVELOPMENT..AND
THERE IS A LOW CHANCE...LESS THAN 30 PERCENT...OF THIS SYSTEM
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. HOWEVER...
THIS WEATHER SYSTEM SHOULD MOVE SLOWLY NORTHWARD DURING THE NEXT
COUPLE OF DAYS...BRINGING LOCALLY HEAVY RAINS TO PORTIONS OF THE
SOUTHEASTERN UNITED STATES. FOR ADDITIONAL INFORMATION ON THE
POTENTIAL FOR HEAVY RAINFALL...PLEASE CONSULT PRODUCTS BEING ISSUED
BY YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST OFFICE.

A BROAD AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL IS PRODUCING
DISORGANIZED SHOWERS AND THUNDERSTORMS EXTENDING FROM THE WEST
COAST OF AFRICA TO SOUTHEAST OF THE CAPE VERDE ISLANDS. DEVELOPMENT
OF THIS SYSTEM...IF ANY...IS EXPECTED TO BE SLOW TO OCCUR AS IT
MOVES WEST- NORTHWESTWARD AT 10 TO 15 MPH. THERE IS A LOW
CHANCE...LESS THAN 30 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER KIMBERLAIN/BROWN

[wxman57]

Looks like we do have a surface low this morning. Very weak, as expected. Located about 65 miles east of Corpus Christi. LONG band of heavy rain extending from northeast of the low, southward all the way to the Bay of Campeche. Going to be a very rainy next 24-48 hours from east TX through SW an south-central LA.

[attallaman]

On weather radar this morning there's heavy rain all the way to the WC of FL. Is the rain currently along the WC of FL related to the TX system? The reason I ask someone started another thread stating we should be watching the EGOM near FL for possible tropical development and not be focusing so much of our attention on the WGOM and the TX system.

[tailgater]

Thanks for the GARP, I was trying to find some way to post the low on my simple charts. Did you notice the pressure drops off to the east of Corpus Christi?


Conditions at 42019 as of
(6:50 am CDT)


Wind Direction (WDIR): SE ( 140 deg true )
Wind Speed (WSPD): 4.0 m/s
Wind Gust (GST): 5.0 m/s
Wave Height (WVHT): 0.6 m
Dominant Wave Period (DPD): 6 sec
Average Period (APD): 4.5 sec
Mean Wave Direction (MWD): NE ( 51 deg true )
Atmospheric Pressure (PRES): 1006.8 mb
Pressure Tendency (PTDY): -0.5 mb ( Falling )

[HurryKane]

Looking at the radar this morning and could swear I see a spin (in the precipitation) directly south of Bay St. Louis.

[Frank P]

Looking at the radar this morning and could swear I see a spin (in the precipitation) directly south of Bay St. Louis.

yeah, that's an interesting little twist.. also looks like some banding associated with it... this whole mess in the GOM might be generating little weak spins all over the place... this could be one of them...

[tailgater]

Another threat, I guess with the Upper, MID and Lower level vortices's There is alot of mixing going on.



http://www.intellicast.com/National/Rad ... n=USTX0270

[jinftl]

Graphic from NOAA:



http://www.ssd.noaa.gov/PS/TROP/TCFP/da ... inrfps.png

[Diva]

Good grief! The whole Gulf is a percolator based on that graphic!

[HURAKAN]

Station 42020 (LLNR 1330) - Corpus Christi, TX 50NM Southeast of Corpus Christi, TX

Conditions at 42020 as of
(6:50 am CDT)
1150 GMT on 09/12/2009:

Wind Direction (WDIR): W ( 260 deg true )
Wind Speed Wind Speed (WSPD): 9.7 kts
Wind Gust Wind Gust (GST): 11.7 kts
Wave Height Wave Height (WVHT): 2.3 ft
Dominant Wave Period Dominant Wave Period (DPD): 5 sec
Average Period Average Period (APD): 3.7 sec
Mean Wave Direction Mean Wave Direction (MWD): SE ( 140 deg true )
Atmospheric Pressure Atmospheric Pressure (PRES): 29.75 in
Pressure Tendency Pressure Tendency (PTDY): -0.02 in ( Falling )
Air Temperature Air Temperature (ATMP): 80.4 °F
Water Temperature Water Temperature (WTMP): 82.8 °F
Dew Point Dew Point (DEWP): 74.8 °F
Heat Index Heat Index (HEAT): 85.6 °F

Link: http://www.ndbc.noaa.gov/station_page.php?station=42020

[jinftl]

Shear in the Gulf and NW Caribbean has decreased quite a bit from values we have been seeing most of the season



As noted in another thread, Tropical Cyclone Heat Potential remains at explosive levels south of cuba and around the cayman islands to Cancun and back to Jamaica Fairly high values in the western Gulf. The Loop Current is not making its presence known as in prior years in the central gulf however.



Lower shear, high tchp, very warm water.....

[HURAKAN]

An invest may be declared at any moment if the NHC believes this is the LLC they have been waiting for.

[wxman57]

Sat pic of Gulf looks similar to Allison of 2001. Differences are that this low is MUCH weaker, less organized, and closer to the coast. So I don't think it will become a TD before it moves inland. But the rainfall potential for SE TX and SW LA is tremendous.

[attallaman]

Good grief! The whole Gulf is a percolator based on that graphic!

The rain appearing on radar right now stretching all the way along the FL panhandle and down along the WC of FL, is that rain along the panhandle area and the WC of FL part of this TX system or is that the result of something else trying to develop in the EGOM?

[Comanche]

Sat pic of Gulf looks similar to Allison of 2001. Differences are that this low is MUCH weaker, less organized, and closer to the coast. So I don't think it will become a TD before it moves inland. But the rainfall potential for SE TX and SW LA is tremendous.

ENOUGH WITH THE TEASING! If it was an Allison repeat, it would skip my house!

[TampaFl]

Good grief! The whole Gulf is a percolator based on that graphic!

The rain appearing on radar right now stretching all the way along the FL panhandle and down along the WC of FL, is that rain along the panhandle area and the WC of FL part of this TX system or is that the result of something else trying to develop in the EGOM?

From NWS TLH AFD:

000
FXUS62 KTAE 120712
AFDTAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
310 AM EDT SAT SEP 12 2009

.SYNOPSIS...
07Z WATER VAPOR AND H4 RUC ANALYSIS SHOWING ONE OF THE MORE COMPLEX
UPPER LEVEL PATTERN THIS FORECASTER HAS SCENE...AND ESPECIALLY SO
FOR MID SEPTEMBER. ONE COULD WRITE A BOOK IN TRYING TO DESCRIBE ALL
THE INTERACTING UPPER LOW FEATURES...BUT FOR THE SAKE OF BREVITY
WILL KEEP THIS SIMPLE. FROM WEST TO EAST ACROSS THE CONUS WE FIND
AMPLIFIED UPPER RIDGING ACROSS MUCH OF THE INTERMOUNTAIN WEST. THIS
RIDGING IS QUICKLY REPLACED DOWNSTREAM BY A POTENT UPPER DISTURBANCE
DROPPING STRAIGHT SOUTH OVER THE HIGH PLAINS. BELOW THIS SYSTEM IS
YET ANOTHER ORGANIZING CUT OFF LOW SPINNING OVER SOUTHERN/EASTERN
TEXAS. FINALLY...ONE MORE OLDER AND WEAKENING UPPER LOW CONTINUES TO
SPIN OVER THE MID-ATLANTIC/NE STATES. IT IS THE EFFECTS OF THE
ENERGY OVER TEXAS THAT WILL BE OUR MAIN FORECAST IMPACT THROUGH THE
WEEKEND.

AT THE SURFACE...LOW PRESSURE ASSOCIATED WITH THE INFLUENCE OF THE
TEXAS UPPER LOW CONTINUES TO BECOME BETTER ORGANIZED OVER THE
WESTERN GULF OF MEXICO/TEXAS COAST. PRESSURE PATTERN AND SURFACE
OBSERVATIONS SUGGEST FRONTOGENESIS CONTINUES TO THE EAST OF THIS
LOW...WITH A FAIRLY WELL-DEFINED WARM-FRONTAL FEATURE NOW EXTENDING
ACROSS THE CENTRAL/EASTERN GULF OF MEXICO. NUMEROUS SHOWERS AND
EMBEDDED THUNDERSTORMS HAVE DEVELOPED ALONG AND TO THE NORTH OF THIS
BOUNDARY OVER THE NORTH-CENTRAL/NE GULF OF MEXICO WATERS. OVER OUR
LAND ZONES... THE FLOW IS FROM THE EAST AND NORTHEAST AROUND A HIGH
PRESSURE RIDGE TO OUR NORTH.

&&

.SHORT TERM (TODAY THROUGH MONDAY)...
GFS/ECMWF ARE IN VERY GOOD AGREEMENT WITH THEIR RESPECTIVE SYNOPTIC
FEATURES THROUGH THE WEEKEND. TEXAS UPPER LOW WILL CONTINUE TO
DEEPEN AND BECOME BETTER ORGANIZED THROUGH THE MORNING HOURS. AS
THIS OCCURS THE RESULTING SURFACE REFLECTION/LOW WILL ALSO CONTINUE
TO ORGANIZE TO OUR WEST ALONG THE UPPER TEXAS COAST. VERY
UNSEASONABLY WARM FRONTAL FEATURE EXTENDING EAST FROM THIS LOW
ACROSS THE NORTHERN GULF WILL MOVE SLOWLY NORTH ACROSS OUR MARINE
LEGS THIS MORNING REACHING THE COASTAL AREAS THIS AFTERNOON. DEEP
MOISTURE IS SPREADING NORTH HELPING TO SET UP A POTENTIALLY RAINY
DAY FOR PORTIONS OF THE FORECAST AREA. IN FACT...00Z GFS IS
INDICATING PW VALUES RAISING WELL ABOVE 2" BY LATER THIS MORNING
ALONG AND SOUTH OF I-10.

LOW LEVEL FOCUS ALONG THE FRONT COMBINED WITH SUBTLE BUT DEEP LAYER
UPGLIDE IS RESULTING IN AN EXTENSIVE AREA OF SHOWER/EMBEDDED STORMS
ACROSS THE NORTHEAST GULF. THIS AREA HAS BEEN VERY SLOW TO MOVE
NORTH DURING THE EVENING HOURS...HOWEVER ALL GUIDANCE INSISTS THAT
THE WARM FRONT WILL BEGIN ITS MARCH NORTHWARD THIS MORNING.
EXPECTING THIS ACTIVITY TO REACH" onClick="return popup(this, 'notes')">REACH THE COASTAL ZONES AROUND SUNRISE
WITH A SLOW INLAND SPREAD TOWARD THE I-10 CORRIDOR DURING THE
MORNING AND EARLY AFTERNOON. MUCH OF OUR ZONES NORTH OF THE FLORIDA
BORDER (ESPECIALLY GA) ACTUALLY SHOULD SEE A FAIRLY DRY
MORNING/EARLY AFTERNOON...WITH RAIN CHANCES INCREASING QUICKLY TO
THE SOUTH AND SOUTHWEST. AS THE FRONT AND ASSOCIATED LIFT FIELDS
OVERSPREAD FROM THE SOUTH...AREAS OF RAIN/EMBEDDED STORMS SHOULD BE
FAIRLY NUMEROUS FOR THE AFTERNOON/EVENING. FAR NORTHERN AREAS PAST
ALBANY AND TIFTON MAY ESCAPE THE RAINFALL FOR MOST OF THE DAY AND
WILL NOT RAISE THE INHERITED CHANCE POP. GOING TO BE A MOSTLY CLOUDY
TO CLOUDY DAY WITH TEMPS HELD IN THE 80S. AS WAS MENTIONED LAST
NIGHT...COASTAL AREAS WHERE THE RAIN BEGINS EARLY IN THE DAY MAY
STRUGGLE OUT OF THE LOWER 80S. OF NOTE...LATEST NAM SOLUTION IS
REALLY STRUGGLING TO BRING PRECIP INLAND FROM THE COAST WITH LITTLE
TO NO RAIN ALONG AND NORTH OF THE I-10 CORRIDOR. THIS SOLUTION IS A
SIGNIF OUTLIER...AND NOTING THAT THE NAM DID NOT INITIALIZE THE
CURRENT CONVECTION VERY WELL...WILL NOT PUT MUCH WEIGHT ON ITS
SOLUTION FOR THIS FORECAST PACKAGE.

WARM FRONT WEAKENS TONIGHT WITH A MORE "BAGGY" PRESSURE PATTERN
LEFTOVER ACROSS THE AREA. ALTHOUGH THE OVERALL COVERAGE AND RAINFALL
INTENSITY SHOULD DIMINISH...ABUNDANT DEEP LAYER MOISTURE AND WEAK
LOW LEVEL FOCUS WOULD SUGGEST THAT LIGHTER AREA OF RAIN/SHOWERS WILL
STILL BE IN THE FORECAST.

BY SUNDAY...THE UPPER LEVELS ACTUALLY GIVE US A BREAK WITH WEAK
RIDGING BUILDING OVER THE EASTERN GULF WHILE THE UPPER LOW REMAINS
OVER TEXAS. WEAK LEFTOVER SURFACE TROUGH SHOULD PROVIDE FOCUS FOR
MORE SUMMER-LIKE AFTERNOON CONVECTION...AS OPPOSED TO THE FRONTAL
PRECIP EXPECTED TODAY. BY MONDAY THE ENTIRE SYSTEM OVER THE SOUTHERN
PLAINS LOOKS TO BEGIN MOVING SLOWLY EAST. FOR NOW...THIS WILL BE
MORE OF AN EXTENDED FORECAST CONCERN WITH MONDAY ENDING UP A
GENERALLY QUIET AND TRANQUIL DAY OUTSIDE A FEW TYPICAL AFTERNOON
SHOWERS OR STORMS.

&&

.LONG TERM...(TUESDAY THROUGH NEXT SATURDAY)...
ALTHOUGH THERE IS STILL SOME UNCERTAINTY IN EXTENDED FORECAST (DUE
MAINLY TO DIFFERENCES IN SHORT TERM SCENARIO)...WHICHEVER MODEL
EVENTUALLY VERIFIES...WE STILL EXPECT THE BULK OF THE EXTENDED FCST
TO BE UNSETTLED...WITH SOME IMPROVEMENT FRIDAY INTO SATURDAY.

BEST "GUESS" SCENARIO SHOWS THE FOLLOWING: THE PERIOD BEGINS WITH
CONUS ANCHORED BY A MEAN TROF OVER ERN CANADA EXTENDING SWWD INTO
THE NE U.S...AND ERN PERIPHERY OF THE NERN PAC TROF EXTENDING INTO
THE PAC NW. IN BETWEEN...AMPLIFIED RIDGING AND WEAK FLOW DOMINATE
CONUS. WEAK RIDGING IS ALSO DENOTED OVER SE CONUS. BY WED THE TROUGH
DIGS INTO NRN GULF ALLOWING RIDGE TO AMPLIFY OVER LOCAL AREA. BY WED
NIGHT TROUGH EXITS OFF NEW ENG WITH CUTOFF UPPER LOW DEVELOPING. AT
BASE. MODELS IN GOOD AGREEMENT THAT AT THIS TIME ANOTHER STRONG
SHORT WAVE PUSHES FROM SRN CA PROGGED INTO WESTERN US HELPING TO
KICK UPPER LOW EWD BUT AS SHORTWAVE LIFTS NEWD AND WEAKENS...LOW
BEGINS TO MEANDER. SO THIS LOW WILL INCH EWD THRU FRI BEFORE IT
OPENS INTO A TROUGH OVER LWR MISS VALLEY AND REMAINS W OF CWA...
KEEPING FORECAST AREA IN SW FLOW. IT ALSO GENERATES CYCLOGENESIS
NEAR GULF COAST AND DEVELOPS WEAKER SURFACE REFLECTION WHICH ALSO
MOVES SLOWLY NE UNDER RIDGE WITH ASSOCD QUASI-STATIONARY FRONT
LINGERING CLOSE TO CWA KEEPING AREA IN AN UNSETTLED WET PATTERN FOR
MOST (OR ALL) OF EXTENDED. THE GFS IS MOST ROBUST ALOFT WITH MOST
OTHER GUIDANCE WEAKER WITH SURFACE REFLECTION SUPPRESSED.

ALTHOUGH MODELS IMPLY AMPLE MOISTURE/RAINFALL THRU EXTENDED PERIOD
...LEVEL OF UNCERTAINTY WILL CAUSE ME TO UNDERCUT MOS POPS AT THIS
POINT. SO GENERALLY GO MID-HIGH SCT POPS THRU PERIOD WITH SOME
LIKELY POPS POSSIBLE DURING INITIAL DAYS. AMPLE CLOUDS COVER WILL
KEEP MIN TEMPS IN LOW 70S OR ABOVE CLIMO (MID-UPPER 60S) UNTIL LAST
FEW DAYS WHEN WITH DECREASING CLOUDS...MINS DROP TO AROUND CLIMO.
MAX TEMPS WILL REMAIN AT OR BELOW CLIMO (87-88 DEGREES) THROUGH THE
PERIOD.

&&

.MARINE...
A WARM FRONT WILL MOVE NORTH ACROSS THE FORECAS