Model Runs & Discussions of GOM-Bahamas

[Stratosphere747]

LOL Steve...

When I asked you about the teleconnection idea, I didn't want you to forecast a LF in my backyard..

Anyways it is something I have become interested in somewhat and how it may relate to this side of the pond. Good stuff and thanks for the input.

[Steve]

No problem. I gotta get my *** to bed anyway, so that's my parting take for the night. I don't see "Cat 5" endgame, But I don't see sheared/weak depression either. When you wake up, go check out the JTWC, storm2k's active page or wherever you get your WPAC shots from and projected tracks. See if Wipha hits Taiwan or not. If so, ridging is stronger. The projected track has moved west over the last three days or so.

Steve

[Stormcenter]

For anyone who is interested here is the Canadian run.

http://moe.met.fsu.edu/cgi-bin/cmctc2.c ... =Animation

[Wx_Warrior]

oh my lands...in all seriousness...Has CMC ever been right or close?

Time to put that thing to bed

[vaffie]

oh my lands...in all seriousness...Has CMC ever been right or close?

Time to put that thing to bed

The Canadian does often have very wacky solutions, that change from run to run, but three days out, it forecast Humberto perfectly showing it develop quickly into a hurricane hitting Beaumont/Port Arthur. Three days before Erin formed, it forecast it perfectly too. At least half a dozen times this season it has forecast the intensity and the track of a developing tropical system very well three or four days before it formed. Granted however that it is not consistent in it's model runs, but it is worth looking at too.

[Wx_Warrior]

Thanks for the explaination!

[southerngale]

150 makes landfall near Beaumont/port arthur...

http://www.nco.ncep.noaa.gov/pmb/nwprod ... n_150s.gif

although I will say that it loses it at 144 for a frame, and then this at 150 at landfall.

Of course that's just one model run, but with several models showing that something *could* potentially affect Texas, it sure is making some folks nervous around here. I just watched a newscast of all Humberto aftermath... the clean-up... the debris piling up by the streets, Salvation Army still out there passing out meals, ice, cleaning kits, etc., insurance issues, FEMA starting surveys this morning, etc. and then all 3 newscasts talk about this and how they'll be watching it. I only watched one station, but heard about the others. One very respected met said, "If it does start to develop, it could become something of some significance on down the road..." but pointed out we have many days to watch and that we're talking late this week if any development occurs at all.

Rita was a pretty late hit for us... surely this one (IF it even develops) will find a weakness before it reaches Texas.

[vaffie]

For what it's worth, the latest WRF model closes off a low in the eastern Gulf of Mexico early Thursday morning, and tracks it slowly WNW-ward so that early on Sunday morning it is south of Lake Charles and southeast of Galveston. It does not strengthen it, but as we all know, intensity is very unpredictable. The main thing is that it's going to be a closed low over the open waters of the warm Gulf of Mexico for 4 whole days--that says enough right there. Once we have an invest at least, the statistical intensity models will help us determine how strong it could be. In my honest opinion, there would have to be tremendous nonstop shear--and I don't see that happening--to keep it from becoming a major hurricane.

http://moe.met.fsu.edu/cgi-bin/hwrftc2. ... =Animation

[Matt-hurricanewatcher]

No, it takes a lot to form a major hurricane. It has to moisten the lower and mid levels of the Atmosphere. Meaning dew points through out the layers have to be at least 65 degrees...So it can't have dry air, with the strong shear that will push the dry air into the core of the LLC. Which slows development of the cyclone. This kind of system like Arlene and Alberto takes time to transform into a classic tropical cyclone. Both storms including Alison 2001, are all what happens when you have dry air at some layer of the Atmosphere or shear to pull that dry air into the system. Since this system has to deal with 20+ knot shear. I do not see if becoming more then a tropical storm,,,It will take time once the shear drops to transform into stated system.

[southerngale]

00Z UKMET

[Meso]

06 NAM

Models seem to be moving it more north in the beginning,and another low in the N.W Caribbean

[xironman]

The migration north makes sense. The upper trough is head south like gangbusters this morning http://www.ssd.noaa.gov/goes/east/se/loop-wv.html. Anything would have to go over the top.

[Meso]

000
ABNT20 KNHC 180847
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
530 AM EDT TUE SEP 18 2007

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

A LARGE AREA OF DISORGANIZED CLOUDINESS AND THUNDERSTORMS EXTENDS
FROM THE EAST COAST OF FLORIDA EASTWARD FOR A FEW HUNDRED MILES OVER
THE WESTERN ATLANTIC AND BAHAMAS. THIS ACTIVITY IS ASSOCIATED WITH
A TROPICAL WAVE AND AN UPPER-LEVEL TROUGH. CONDITIONS ARE
CURRENTLY UNFAVORABLE FOR DEVELOPMENT IN THIS AREA...BUT SLOW
DEVELOPMENT IS POSSIBLE IN A COUPLE OF DAYS WHEN THE SYSTEM MOVES
WESTWARD OVER FLORIDA AND INTO THE EASTERN GULF OF MEXICO. LOCALLY
HEAVY RAINFALL IS POSSIBLE OVER PORTIONS OF THE FLORIDA PENINSULA
AND THE BAHAMAS DURING THE NEXT DAY OR TWO.

THE REMNANTS OF TROPICAL DEPRESSION INGRID ARE LOCATED JUST
NORTHEAST OF THE NORTHERNMOST LEEWARD ISLANDS. REDEVELOPMENT IS
NOT EXPECTED DURING THE NEXT COUPLE OF DAYS AS THIS SYSTEM MOVES
SLOWLY NORTHWESTWARD.

SHOWER ACTIVITY REMAINS LIMITED IN ASSOCIATION WITH A TROPICAL WAVE
LOCATED ABOUT 800 MILES EAST OF THE LESSER ANTILLES. ANY
DEVELOPMENT OF THIS SYSTEM IS EXPECTED TO BE SLOW TO OCCUR AS IT
CONTINUES WESTWARD AT 10 TO 15 MPH.

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

$$

FORECASTER KNABB

[southerngale]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAKE CHARLES LA
449 AM CDT TUE SEP 18 2007

I AM ALSO BECOMING A LITTLE MORE CONCERNED THAT AT LEAST A PARTIAL
TRANSITION TO A TROPICAL SYSTEM...OR SUBTROPICAL DEVELOPMENT...WILL
OCCUR...WITH THE GFS WEAKENING THE LOW...AND THUS THE WINDS...AT
H3...AND SHOWING WARMING TEMPERATURES AT H5. WHILE I WOULD NOT
NECESSARILY PUT A LOT OF STOCK INTO A MODEL ACCURATELY FORECASTING
A MID LATITUDE TO TROPICAL TRANSITION...THE MERE FACT THAT THIS
ENTITY WILL SPEND ANYWHERE FROM 3 TO 4 DAYS OVER THE 85 DEGREE
GULF WATERS LENDS SOME CREDENCE TO THIS POSSIBILITY. WILL BE
INTERESTING TO WATCH WHAT PLAYS OUT LATER THIS WEEK...BUT FOR THE
MOMENT I HAVE REMAINED RELATIVELY CONSERVATIVE WITH POPS/WINDS/SEAS.





AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
400 AM CDT TUE SEP 18 2007

NEXT BEST RAIN CHANCES REMAIN TIED THE POS-
SIBILITY OF SOMETHING DEVELOPING OVER THE GULF. AS PER MODELS WE
ARE STILL LOOKING AT THE EVOLUTION OF AN UPPER LOW (SINKING SSWD
FROM THE ERN SEABOARD AND CUTTING OFF OVER THE NERN GULF) INTO A
SFC CIRCULATION OF SOME KIND BEFORE HEADING TOWARD THE TX COAST.
GFS SOLUTIONS ARE NOW AIMING THIS VISITOR AT SABINE PASS WHEREAS
PREVIOUS RUNS HAVE RANGED FROM CRP TO BPT. WHILE OTHER PROGS ARE
GOING EITHER FURTHER NORTH/SOUTH OF THESE TRACKS...THE TROUBLING
ASPECT OF ALL THIS IS THAT THEY ARE ALL INDICATING A DEVELOPMENT
OF SOME KIND. LOOKS LIKE A BEAR WATCH WILL BE NEEDED FOR THIS UP
COMING WEEKEND.




AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CORPUS CHRISTI TX
337 AM CDT TUE SEP 18 2007

THE RIDGE DOES MOVES NORTH ON SATURDAY AND ATTENTION SHIFTS TO
POSSIBLE DISTURBANCE OVER THE CENTRAL GULF OF MEXICO. THERE ARE
STILL DISCREPANCIES AMONG MODELS WITH REGARDS TO HOW...IF AT
ALL...THIS WILL DEVELOP AND WHERE IT WILL IMPACT ALONG THE WESTERN
OR NORTHERN GULF COAST. IF ANYTHING...THE 12Z AND 00Z MODEL RUNS
OVER THE PAST 24 HOURS HAVE SHIFTED FURTHER NORTHEAST WITH A
BROAD/CLOSED SURFACE CIRCULATION MOVING INLAND MORE TOWARDS THE
UPPER TEXAS COAST OR EVEN LOUISIANA SUNDAY OR MONDAY.




AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
245 AM CDT TUE SEP 18 2007

FORECAST MODELS SUGGEST THAT A
LOW PRESSURE AREA MAY DEVELOP IN THE EASTERN GULF OF MEXICO LATER
THIS WEEK...AND THIS FEATURE COULD THEN SUBSEQUENTLY TRACK WEST
TOWARD THE TEXAS COAST.




AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
447 AM CDT TUE SEP 18 2007

THE MODELS CONTINUE TO SHOW A STACKED LOW PRESSURE SYSTEM...
BAROCLINIC IN NATURE...RESEMBLING AN OCCLUDED SYSTEM EXCEPT MOVING
THROUGH THE EASTERLIES. THE GFS/ECMWF HAVE CONTINUED TRENDING A
BIT SLOWER...BRINGING THE LOW THROUGH THE NORTH CENTRAL GULF OF
MEXICO FRIDAY AND FRIDAY NIGHT AND THE NORTHWEST GULF SATURDAY
INTO SUNDAY...AND INTO THE UPPER TX COAST AROUND SUNDAY NIGHT. IT
REMAINS TO BE SEEN WHETHER OR NOT THIS SYSTEM WILL BE ABLE TO
TRANSITION TO A TROPICAL/HYBRID LOW.




AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
441 AM CDT TUE SEP 18 2007

FORECASTERS ARE WATCHING AN AREA OF DISTURBED
WEATHER...WHICH MANY OF THE LONG RANGE GLOBAL MODELS BRING WESTWARD
INTO THE EASTERN GULF FOR THE LATTER HALF OF THE WEEK. THE CANADIAN
IS A NORTHERN OUTLIER...BRINGING A LOW INTO THE SOUTHEAST WHILE THE
NAVY NOGAPS IS WELL SOUTH WITH A LOW MEANDERING INTO THE SOUTHWEST
GULF. THE UKMET/GFS/AND ECMWF MODELS ARE THE MOST CONSISTENT BRINGING
A LOW WESTWARD ACROSS THE CENTRAL GULF FRIDAY AND SATURDAY WITH
POSSIBLE IMPACTS ANYWHERE FROM THE CENTRAL TEXAS COAST TO SOUTHWEST
LOUISIANA AROUND THE SUNDAY TIME FRAME. THESE SOLUTIONS SEEM TO BE
THE MOST PLAUSIBLE AS UPPER RIDGE BUILDS WESTWARD OVER THE LOWER
MISSISSIPPI RIVER VALLEY AND THEN INTO THE SOUTHEAST. STILL HARD TO
INITIALIZE ANY RUN OVER ANOTHER AS THE ORIGINATION AREA OF ANY LOW IS
IN ITS INFANCY.




AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
329 AM EDT TUE SEP 18 2007

BY LATE WEDNESDAY THE
NAM AND GFS BRING A LARGE AREA OF DEEP LAYER MOISTURE INTO THE
EASTERN PORTIONS OF OUR AREA...WHILE THE ECMWF IS A LITTLE SLOWER.
THIS MOISTURE IS ASSOCIATED WITH A COMPLEX LOW PRESSURE SYSTEM
THAT WILL BE GRADUALLY EVOLVING OVER THE FL PENINSULA AND EASTERN
GULF WEDNESDAY AND THURSDAY. IT IS STILL NOT CLEAR WHETHER THIS
WILL BE MORE OF A TROPICAL CYCLONE (WITH ITS ORIGINS FROM A BROAD
TROPICAL WAVE THAT HAS BEEN TRACKING SLOWLY WESTWARD ACROSS THE
WESTERN ATLANTIC THE PAST 5 DAYS...AS SEEN IN A 5-DAY LOOP OF THE
850 MB VORTICITY FIELD FROM THE UW CIMMS SITE)...OR AN
EXTRATROPICAL LOW GENERATED BY BAROCLINIC FORCING ASSOCIATED WITH
THE COLD CORE LOW CLOSING OFF THE FL PENINSULA. PERHAPS THE ANSWER
IS SOMEWHERE IN BETWEEN. WHATEVER THE CASE...ALL OF THE GUIDANCE
DEVELOPS A SURFACE LOW OVER THE EASTERN GULF...AND USUALLY WHEN
THERE IS THAT STRONG (AND THAT PERSISTENT) OF A CONSENSUS AMONG
THE GLOBAL MODELS...SUCH DEVELOPMENT OCCURS. WE ARE NOT USING THE NAM AS
IT IS AN OUTLIER WITH THIS SYSTEM...TAKING A MUCH STRONGER SYSTEM
MUCH CLOSER TO OUR COAST THAN THE OTHER GUIDANCE. WITH BUILDING
HEIGHTS OVER THE SOUTHEAST U.S. THERE IS BETTER AGREEMENT AMONG
THE VARIOUS GLOBAL MODELS THAT THE LOW WILL TAKE A WESTWARD TRACK
ACROSS THE GULF...PROTECTING OUR AREA FROM ANY LANDFALL (IF THAT
IS A PROPER TERM TO USE HERE). HOWEVER...OUR AREA WILL EXPERIENCE
A PERIOD OF ABOVE-AVERAGE POPS ON THURSDAY AS Q-G FORCING COMBINES
WITH INCREASED DEEP LAYER MOISTURE. HOWEVER...WE DID NOT GO TOO
HIGH WITH OUR POP (GENERALLY 50 PERCENT OR LESS) AS THE GLOBAL
MODELS HAVE BEEN TRENDING FARTHER SOUTH WITH THE LOW TRACK WITH
EACH MODEL RUN...AND THIS IS GOING TO BE SUCH A COMPLEX SYSTEM
THAT IT WILL LIKELY HAVE ZONES OF STRONG SUBSIDENCE INTERRUPTED
WITH BANDS OF RAIN...AND THIS IS ALMOST IMPOSSIBLE TO FORECAST
THIS FAR OUT.




AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
241 AM EDT TUE SEP 18 2007

THE WEATHER PATTERN APPEARS TO BE
EVOLVING JUST AS THE GFS HAS BEEN SUGGESTING. A SHARP UPPER-LEVEL
TROUGH IS EVIDENT IN SATELLITE IMAGERY EXTENDING NORTHEAST TO
SOUTHWEST DOWN THE EASTERN SEABOARD. THERE IS EVEN EVIDENCE THAT
THE UPPER-LEVEL LOW MAY BE CLOSING OFF JUST EAST OF THE PENINSULA.
THIS FEATURE WILL MOVE ACROSS THE PENINSULA TONIGHT AND
WEDNESDAY...THEN INTO THE EASTERN GULF WEDNESDAY NIGHT AND
THURSDAY. WHILE THE UPPER-LEVELS SEEM STRAIGHT FORWARD ENOUGH...
IT`S THE SURFACE EVOLUTION THAT IS ANYTHING BUT CLEAR...AND THIS
MAKES FOR A LOW CONFIDENCE FORECAST THIS MORNING.

WE ARE COMPLETELY DISCOUNTING THE NAM AS IT TRIES TO DEVELOP A
STRONGER SURFACE SYSTEM IN THE BAHAMAS TONIGHT...WHICH THEN MOVES
ACROSS THE NORTHERN HALF OF FLORIDA WEDNESDAY NIGHT. THERE IS WAY
TOO MUCH SHEAR FOR SIGNIFICANT TROPICAL DEVELOPMENT AT THIS
TIME...ALTHOUGH CONDITIONS COULD BECOME LESS HOSTILE AFTER IT
ENTERS THE GULF. WE WILL STICK WITH THE GFS SOLUTION OF DRAGGING A
WEAK SURFACE TROUGH ACROSS THE PENINSULA UNDER THE UPPER-LEVEL
LOW...WITH ANY SIGNIFICANT DEVELOPMENT OCCURRING AFTER THE SYSTEM
IS WELL WEST OF OUR REGION.







AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL

MODELS GETTING INTO FAIRLY GOOD AGREEMENT THAT A CLOSED UPPER LOW
...NOTED CURRENTLY IN SATL LOOPS OFF THE CENTRAL FLA COAST...WILL
SLOWLY MOVE WSW ACROSS THE FLA PENINSULA TONIGHT INTO WED AND INTO
THE GULF WED NIGHT. SOME DIFFERENCES THOUGH IN SURFACE EVOLUTION AS
NAM WANTS TO INTERACT WITH THE INVERTED TROUGH (WAVE?) AND FORM A
SURFACE LOW...WHICH MOVES N ALONG THE FLA COAST WHILE THE GFS KEEPS
THE INVERTED TROUGH...WHICH MOVES WESTWARD ACROSS S FLA TONIGHT AND
INTO THE GULF WED. MORE MODELS LEAN TOWARD GFS SOLUTION AS WILL THIS
FORECAST.






AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
355 AM EDT TUE SEP 18 2007

MODELS IN GOOD AGREEMENT THAT THE UPPER LOW WILL CONTINUE
TO SLIDE WESTWARD INTO THE CENTRAL/EASTERN GULF. SURFACE DEVELOPMENT
IN THE FORM OF A TROPICAL DEPRESSION OR EXTRA-TROPICAL CLOSED LOW
SEEMS LIKE A STRONG POSSIBILITY. HOWEVER...CONFIDENCE IS HIGH THAT
THIS SYSTEM WILL HAVE A WANING INFLUENCE ON THE STATE AS A STRONG
RIDGE OVER THE DEEP SOUTH STEERS IT STEADILY WESTWARD ACROSS THE
GULF. SUFFICIENT MOISTURE IN ITS WAKE WILL RESULT IN SCATTERED
SHOWERS AND THUNDERSTORMS EACH DAY THROUGH THE WEEKEND. GFS MAY BE A
BIT OVERDONE IN ITS DEPICTION OF DEEP TROPICAL MOISTURE STREAMING
NORTHWARD DURING THE WEEKEND. DRIER ECMWF IS PREFERRED...ESPECIALLY
IF THE SYSTEM IN THE GULF DEVELOPS INTO A DISTINCT ENTITY. DRIER
AIRMASS WOULD BUILD ACROSS THE REGION AS A RIDGE ALONG THE EAST
COAST REINFORCES THE ONSHORE FLOW.

[caneman]

Looks to me like the process is beginning in the central Bahamas right now. Anyone have the 06 GFS? Boy, the GFS has been money this year.

[Matt-hurricanewatcher]

If there is more then 12-15 knots of shear this thing won't have a chance to become more then a Arlene or Alberto like storm. Models show shear around that level. If it lessens for a short time maybe we could get a cat1 hurricane, but that would likely be short lived as some models forecast a increase of the shear over the western gulf.

[xironman]

Things don't quite down up top until Thursday
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/gfs/06/images/gfs_200_048m.gif
From there to Saturday seems like the window in the north central gulf
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/gfs/06/images/gfs_200_096m.gif
So that is where we find our friend.
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/gfs/06/images/gfs_pcp_096m.gif
But like Matt said, on Sunday the upper level winds go wild
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/gfs/06/images/gfs_200_120m.gif
Either it develops fast or it doesn't come about, the GFS kills it Sunday.

[Sanibel]

Starting to convect a little better east of Florida. Still looks too scattered and dry for now. We really need a 5 inch rain here, so if that wave passes over us it would be a good thing.

[cycloneye]

NEW TROPICAL STORM FORECAST TO DEVELOP AFTER 60 HOURS

FORECAST POSITION AT T+ 60 : 26.0N 85.1W



VERIFYING TIME POSITION STRENGTH TENDENCY

-------------- -------- -------- --------

12UTC 20.09.2007 26.0N 85.1W WEAK

00UTC 21.09.2007 24.6N 86.7W WEAK WEAKENING SLIGHTLY

12UTC 21.09.2007 25.6N 87.4W WEAK LITTLE CHANGE

00UTC 22.09.2007 25.7N 89.2W WEAK LITTLE CHANGE

12UTC 22.09.2007 25.5N 91.5W WEAK LITTLE CHANGE

00UTC 23.09.2007 26.5N 93.1W WEAK LITTLE CHANGE

12UTC 23.09.2007 28.0N 94.2W WEAK INTENSIFYING SLIGHTLY

00UTC 24.09.2007 28.6N 95.4W WEAK LITTLE CHANGE



The 00z UKMET makes landfall near Freeport,Texas

[ronjon]

I know upper level winds are strong but that is one huge mass of convection developing east of the FL peninsula. If the UL winds subside even slightly, there may be an opportunity for something to develop. At the very least, looks like a welcome rainmaker for a rather dry FL.

http://www.ssd.noaa.gov/goes/east/watl/loop-rb.html