Ed Dunham
Meteorologist & CFHC Forum Moderator
Reged: Sun
Posts: 2090
Loc: Melbourne, FL
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Its not an Invest yet, but I'll start the thread so we'll have a place for the speculation.
Looks like an embryonic system trying to crawl through the Yucatan Channel. WesnWylie alerted me to the potential for this on Monday - and some of the models are now starting to develop a system in the Gulf. The 31/00Z has a most interesting (and troublesome) solution.
ED
Edited by MikeC (Fri Sep 02 2011 09:32 PM)
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danielw
Moderator
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Posts: 3384
Loc: Hattiesburg,MS (31.3N 89.3W)
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MODEL DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1051 AM EDT WED AUG 31 2011 edited~danielw
12 minutes old at time of post
VALID AUG 31/1200 UTC THRU SEP 04/0000 UTC
...DISTURBANCE IN THE GULF OF MEXICO...
FOLLOWING THE SAME TREND AS YESTERDAY...THE REMAINS THE
NORTHERN MOST AND DEEPEST SOLUTION WITH THE LOW PRESSURE SYSTEM IN
THE GULF ON DAY 2. THERE IS LITTLE AGREEMENT AMONGST THE
OPERATIONAL MODELS WITH RESPECT TO THE LOW LOCATION WHEN IT MOVES
INTO THE NORTHERN GULF AND EVENTUALLY ONSHORE. THE 00Z AND
CMC TAKE THE LOW INTO TEXAS...BUT THE IS MUCH STRONGER THAN
THE . THE 06Z AND 00Z UKMET TAKE THE SYSTEM INTO
LOUISIANA AND MISSISSIPPI...WITH THE UKMET CARRYING THE STRONGER
SOLUTION. THE 12Z STARTS WITH VERY DISORGANIZED SHORTWAVE
ENERGY STRUNG OUT ALONG THE TEXAS...LOUISIANA AND MISSISSIPPI
COASTS AT F48 FRIDAY MORNING...WHICH IS 12 HOURS EARLIER THAN MOST
OTHER OPERATIONAL MODELS INDICATE. THE CONTINUES TO BE ONE OF
THE STRONGEST SOLUTIONS...EVENTUALLY ROTATING THE BULK OF THE
ENERGY WESTWARD INTO EAST TEXAS BY THE END OF THE FORECAST PERIOD.
Latest Model Discussion
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danielw
Moderator
Reged: Wed
Posts: 3384
Loc: Hattiesburg,MS (31.3N 89.3W)
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This link is time sensitive. And, it's for the Eastern Pacific.
GFDL 06Z run for E Pac 93E. Watch the Northern GOM.
http://moe.met.fsu.edu/cgi-bin/gfdltc2.c...;hour=Animation

HWRF Run at 06Z 31 AUG 11. Time Sensitive link
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Ed in Va
Weather Master
Reged: Fri
Posts: 488
Loc: 36.02N 75.67W
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Not sure how accurate this is...this has come up before...when there is a storm other than the one in focus (epac in this case), readings on other storms don't seem to make any sense. There was a case a year or two ago when showed radically different modeling on the same storm...once when it was that storm and once when it showed up on the model for another storm.
-------------------- Survived Carol and Edna '54 in Maine. Guess this kind of dates me!
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Ed Dunham
Meteorologist & CFHC Forum Moderator
Reged: Sun
Posts: 2090
Loc: Melbourne, FL
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You are correct - it is caused by a difference in the model resolution. Fine grid resolution around the storm that the model is focusing on and course grid output elsewhere. For this reason, always dial up the output for the storm of interest.
The area in question is now up to a 30% probability of tropical cyclone development within the next 48 hours.
ED
Edited by Ed Dunham (Wed Aug 31 2011 02:54 PM)
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doug
Weather Analyst
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Posts: 773
Loc: parrish,fl 27.53N 82.44W
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I asked on the News/Talkback the question about What IF: the GOM system pops in 48hours or so...what affect if any would that have on the dynamical situation in the ATL relative to Katia's project recurvature?
-------------------- doug
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Ed Dunham
Meteorologist & CFHC Forum Moderator
Reged: Sun
Posts: 2090
Loc: Melbourne, FL
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For the first 48 hours or so, not much impact - here's why: At 31/18Z a weak circulation was noted near 25N 87W moving west northwest at 15 mph. This is on the northwest edge of the possible development area, so it may just be transitory, i.e., if a system does develop it might be a little further to the south. A weak upper level system was also noted south of Pensacola moving north, and a zone of dry air well to the northwest of the surface feature is moving rapidly westward. It looks like the dry air is not going to be a factor that would influence development. A strong westerly shear zone in the northern Gulf should retrograde westward by Friday. SSTs - approaching 31C - would certainly favor development, while the upper windshear would hinder it - until Friday.
If in the four to five day timeframe the Gulf low develops and gets quite strong, it would have a tendency to create a stronger weakness between itself and Katia. That doesn't mean that Katia would pull closer to the new Gulf system (i.e., the Gulf system might pull closer to Katia) but it could happen since tropical cyclones follow the path of least resistance. The current solution keeps Katia as the predominant system and nudges Katia with a little more of a westward component - which could be an eventual threat to maybe Newfoundland, but not yet the Islands of the northern Caribbean. The eventual movement of the new system as noted in some of the model outputs seems to be more asociated with steering currents and less associated with any influence from Katia. Right now it really is a 'what if' scenario that requires waiting on what might happen in the Gulf.
ED
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Ed Dunham
Meteorologist & CFHC Forum Moderator
Reged: Sun
Posts: 2090
Loc: Melbourne, FL
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The Gulf system is now tagged as Invest 93L. initial coordinates at 31/18Z were 24N 86W. For the initial model input, used 24.1N 87.0W. Here is the initial UKMET output:
NEW TROPICAL STORM FORECAST TO DEVELOP AFTER 60 HOURS
FORECAST POSITION AT T+ 60 : 28.2N 93.4W
VERIFYING TIME POSITION STRENGTH TENDENCY
-------------- -------- -------- --------
00UTC 03.09.2011 28.2N 93.4W WEAK
12UTC 03.09.2011 28.2N 92.7W WEAK INTENSIFYING SLIGHTLY
00UTC 04.09.2011 28.0N 92.7W WEAK LITTLE CHANGE
12UTC 04.09.2011 28.4N 92.2W MODERATE INTENSIFYING RAPIDLY
00UTC 05.09.2011 28.0N 92.9W STRONG INTENSIFYING SLIGHTLY
12UTC 05.09.2011 27.6N 92.7W STRONG INTENSIFYING SLIGHTLY
00UTC 06.09.2011 27.1N 92.4W STRONG LITTLE CHANGE
12UTC 06.09.2011 27.5N 92.9W INTENSE INTENSIFYING SLIGHTLY
ED
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danielw
Moderator
Reged: Wed
Posts: 3384
Loc: Hattiesburg,MS (31.3N 89.3W)
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QUANTITATIVE PRECIPITATION FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
537 PM EDT THU SEP 01 2011
FINAL DAY 1...DAY 2 AND DAY 3 DISCUSSION
VALID SEP 02/0000 UTC THRU SEP 05/0000 UTC
REFERENCE AWIPS GRAPHICS UNDER...PRECIP ACCUM - 24HR
edited~danielw
DAY 2...
CNTRL GULF COAST...
THERE HAS BEEN CONVERGENCE IN MODEL SOLNS WITH RESPECT TO THE
POTENTIAL CYCLOGENESIS OVR THE NCNTRL GULF OF MEXICO DAY 1 INTO
DAY 2. THE CONTS TO BE THE STRONGEST WITH THE DEPTH OF THIS
SYSTEM..WITH CONTINUED LOW CONFIDENCE IN DETAILS. HOWEVER..WITH
THE PSN OF THE SFC LOW MORE SIMILAR THAN IN PAST RUNS...CONFIDENCE
ON HEAVY TO EXCESSIVE RAINFALL AMTS HAS INCREASED. OVERALL...PCPN
DISTRIBUTION AMONG THE LATEST GUIDANCE IS FAIRLY SIMILAR FOR DAY
2. VERY HEAVY RAINFALL AMTS POSSIBLE ALONG THE CNTRL GULF COAST
WHERE PW VALUES 2.5-2.75"+ POSSIBLE AND IF THE STORM BECOME
ORGANIZED...VERY INTENSE RAINFALL RATES WL OCCUR. AMTS IN EXCESS
OF 5" POSSIBLE DAY 2 OVR SRN LA INTO FAR SRN MS AND FAR SRN AL.
THIS WL BRING DAY TOTALS OF 5-10" FROM NEW ORLEANS SEWD TO THE
MOUTH OF THE MS RIVER...WITH INCREASING CHANCES OF RUNOFF
ISSUES...ESPECIALLY IN URBANIZED AREAS.
DAY 3...
CNTRL GULF COAST...
BIGGEST FCST UNCERTAINTY DAY 3 WILL BE THE EVOLUTION OF THE LOW
OVR THE NCNTRL GULF...WHETHER IT MOVES INLAND AS PER THE NAM/GFS
OR STAYS JUST OFF THE SHORE AS PER THE . EITHER WAY...THE
ONE MODEL SIGNAL THAT IS CONSISTENT IS THAT IT WILL BE SLOW MOVG.
THIS WL SUPPORT ADDITIONAL VERY HEAVY RAINFALL POTENTIAL ALONG
PORTIONS OF THE CNTRL GULF COAST WHERE PW VALUES WL BE IN THE
2.25-2.75"+ RANGE. THREE DAY TOTALS IN EXCESS OF A FOOT POSSIBLE
OVR SERN LA. WHILE CURRENT FFG VALUES ARE CURRENTLY HIGH...THE
PERSISTENT HEAVY RAINS OVR THE NEXT 3 DAYS WL INCREASE RUNOFF
THREAT...ESPECIALLY IN URBANIZED AREAS. FOR DETAILS...TRENDED
TOWARD THE SREF MEAN AND LATEST FCSTS...WHICH ARE A LITTLE
SLOWER TO MOVE PCPN INLAND COMPARED TO THE MORE PROGRESSIVE
NAM/GFS SOLNS.
Latest BAM suite indicates the system should stay south of the Louisiana Coast through Day 5, or 120 hours.
All interests in Louisiana south of Interstates 10 and 12 should pay extremely close attention to this system.
People in Alabama and the Florida Panhandle, especially those South of Interstate 10. Should also pay close attention to this system
These are based on current forecasts. And may or may not change.
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MichaelA
Weather Analyst
Reged: Thu
Posts: 788
Loc: Pinellas Park, FL 27.83N 82.69W
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The models should become more definitive since we now have a center location to work with. All have shown a slow moving to stationary system just south of the mid-Gulf coast for several days. Folks east of the center of whatever develops are in for several days of periodic heavy rainfall if the model scenarios play out.
-------------------- Michael
2013: 17/6/4
2013 Actual:
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LoisCane
Senior Storm Chaser
Reged: Fri
Posts: 1198
Loc: South Florida
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Okay well my question is that that much of Lee's moisture way off shore in the Eastern Gulf of Mexico I'm wondering how that plays into the models and if Lee gets cut off in the SE as I have seen many people say he would then could that moisture get cut off or will it keep funneling up.
http://www.ssd.noaa.gov/goes/east/tatl/flash-wv.html
-------------------- http://hurricaneharbor.blogspot.com/
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Joeyfl
Weather Guru
Reged: Mon
Posts: 101
Loc: St.Pete,FL
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NAM is very interesting model with respect to Lee. It drifts Lee about where it is for next 18-24hrs then moves due south into Gulf, while a new low forms over southern Alabama. This seems a little far fetched considering. The is not good model when comes to tropical systems, but somewhat interesting since its shown this in the past few runs. I'll stick with , trough should be enough to pick Lee up and take northeast. Have to go with the consistent on Lee along with Katia.
On side note should be noted in about weeks time the shows new low forming in southern Gulf of Mexico and moving Northeast from around Yucatan region. Its just something to keep an eye on as has preformed very well 7-14 day range in developing tropical systems. It does look overly intense but keep an eye on it, also watch Caribbean around same time as shows large cane there too.
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MichaelA
Weather Analyst
Reged: Thu
Posts: 788
Loc: Pinellas Park, FL 27.83N 82.69W
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Looks like the moisture finally wrapped around Lee's CoC this AM and he's moving off, slowly, to the NE. Still going to dump a lot of rain on LA, MS, and AL and, probably on northeastward into the Blue Ridge region. The strongest rain band is still well to Lee's East, though.
-------------------- Michael
2013: 17/6/4
2013 Actual:
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