See latest as Tropical Storm Ida becomes Hurricane Ida and enters Gulf CLICK HERE
Former Hurricane Ida is moving along as expected so far and for the next day or so, there is a pretty fair consensus on what is going to happen. After that, well…there are a lot of scenarios. Reports from Honduras and Nicaragua claim rain totals of up to 20 inches in some locations with some flooding and wind damage from the initial impact when Ida was a minimal hurricane. It quickly fell back to a tropical depression and, almost exactly as forecast, moved offshore of the northeast coast of Honduras on Friday evening. Ida emerged with a circulation but with the bulk of the convection on the northern half. The southern half of the storm was almost void of any convective activity. However, after just a few hours offshore, substantial convection began exploding in all sectors. The intensity forecast is difficult to determine but this sudden burst makes me think its going to be interesting. A couple of models suggest it becoming a hurricane again, but the NHC is dismissing those, citing an idea that wind shear will develop and prevent such an solution.
Over the next couple of days, Ida is expected to get a little better organized as it moves with a general northern component through the Yucatan Channel, though places like Cancuun and Cozumel will be affected. Unlucky for tourists. A cold front is still looking to move into the Gulf of Mexico by Tuesday and begin to influence the storm. The National Hurricane Center has gone with the idea that the southwesterly shear from the trof will transform Ida into an Extra-Tropical Storm. That means that the physical structure will go from a tropical low, which is a warm core low, to a cold core low. Pragmatically, that is not so much of a big deal because extra-tropical storms can produce extremely strong winds and bring excessive rains. I would think that the storm would get swept northeast. But, there have been several models that want to take the storm back to the southeast once it gets into the Northwest Gulf.
I have to be honest. This is extremely complex. There is another area of disturbed weather in the Bay of Campeche and the models are all over the place. I don’t think the Southwest Gulf system will do much except draw a lot of moisture into the US Central Gulf Coast but I do think its presence is helping to confuse the models. The discussion from the NHC (see below) is no help and provides no explanation. My maps don’t go far enough south to provide an answer as to why the storm would go back southeast instead of getting picked up by the trof and scooted northeast. I am left to assume that the answer is that Ida gets by passed by the trof crossing the United States and leaves it behind or it gets shoved south by the front. But, what leaves me a bit befuddled is that, if it is involved with the trof sufficiently to transform it to a extra-tropical storm, I would think that the trof would have enough influence to pick it up. I’ve got models running deep lows anywhere from New Orleans to Tallahassee or back to the southeast with a couple taking it northeast. This points out the difficulty of models to pick up on not fully developed tropical systems. These models are designed for tropical cyclones and when they turn extra tropical, the models can get confused…and so am I. Stay tuned.
WTNT41 KNHC 070233
TROPICAL DEPRESSION IDA DISCUSSION NUMBER 11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL112009
1000 PM EST FRI NOV 06 2009
A 2302 UTC SSMIS MICROWAVE PASS INDICATED THAT THE LOW-LEVEL CENTER
OF IDA WAS LOCATED JUST OFF THE NORTHEASTERN COAST OF HONDURAS AND
WAS DISPLACED TO THE SOUTH AND SOUTHEAST OF THE DEEP CONVECTION.
NEW CONVECTION IS DEVELOPING CLOSE TO THE CENTER…AND DVORAK
ESTIMATES FROM TAFB AND SAB ARE 25 KT AND 30 KT…RESPECTIVELY.
NOAA BUOY 42057…LOCATED ABOUT 150 N MI EAST-NORTHEAST OF THE
CENTER…RECENTLY REPORTED A 1-MINUTE SUSTAINED WIND OF 35 KT…BUT
IT APPEARS THAT THIS OCCURRED WITH THE PASSAGE OF A SQUALL AND MAY
NOT BE REPRESENTATIVE OF THE OVERALL CIRCULATION. THEREFORE…IDA
IS KEPT AS A TROPICAL DEPRESSION FOR THIS ADVISORY…BUT IT IS
PROBABLY VERY CLOSE TO REGAINING TROPICAL STORM STATUS.
IDA CONTINUES TO MOVE NORTHWARD AT 360/6. A MID-LEVEL ANTICYCLONE
BETWEEN JAMAICA AND HISPANIOLA AND A DEEP-LAYER TROUGH OVER MEXICO
ARE EXPECTED TO STEER IDA NORTH-NORTHWESTWARD THROUGH THE NEXT 72
HOURS. THE TRACK GUIDANCE IS IN GOOD AGREEMENT DURING THIS PERIOD
ALTHOUGH THE GFDL AND HWRF MODELS ARE THE EASTERNMOST MODELS AND
HAVE FORCED THE MODEL CONSENSUS A LITTLE MORE TO THE EAST. THE
FORECAST BEYOND 72 HOURS IS STILL COMPLEX AND IS DEPENDENT ON HOW
IDA INTERACTS WITH THE FRONT AND SHORTWAVE TROUGH OVER THE GULF OF
MEXICO. MOST OF THE GUIDANCE SHOWS IDA BECOMING EXTRATROPICAL BY
96 HOURS ONCE IT MERGES WITH THE FRONT…BUT THE SOLUTIONS VARY ON
WHERE THE LOW GOES NEXT. ONLY THE 1200 UTC ECMWF AND UKMET SHOW
IDA BECOMING PICKED UP BY A SHORTWAVE TROUGH AND MOVING
NORTHEASTWARD OVER THE NORTHERN GULF. THE OTHER MODELS INDICATE A
MORE PRONOUNCED SOUTHWARD MOTION AFTER 96 HOURS…AND THE OFFICIAL
FORECAST NOW SHOWS A SLOW SOUTHEASTWARD TURN AT 120 HOURS.
ALTHOUGH WATERS ARE WARM OVER THE NORTHWESTERN CARIBBEAN…VERTICAL
SHEAR IS EXPECTED TO HAMPER MUCH INTENSIFICATION OVER THE NEXT FEW
DAYS. THE GFDL AND HWRF MAKE IDA A HURRICANE OVER THE CENTRAL GULF
OF MEXICO…A SCENARIO THAT DOES NOT SEEM PLAUSIBLE IN THE FACE OF
WESTERLY SHEAR THAT IS EXPECTED TO INCREASE TO 50 OR 60 KT BY DAY
4. THE OFFICIAL FORECAST INDICATES SOME SLOW STRENGTHENING OVER
THE NEXT SEVERAL DAYS BUT PEAKS THE INTENSITY AT 45 KT…WHICH IS
JUST BELOW THE INTENSITY CONSENSUS.
IT IS OF NOTE THAT MOST OF THE GLOBAL MODELS ARE SHOWING A LARGE
PRESSURE GRADIENT BETWEEN A HIGH OVER THE SOUTHEASTERN UNITED
STATES AND THE TROPICAL CYCLONE. THIS COULD CONTRIBUTE TO A LARGE
AREA OF STRONG WINDS OVER THE GULF OF MEXICO NOT DIRECTLY
ATTRIBUTABLE TO IDA.
FORECAST POSITIONS AND MAX WINDS
INITIAL 07/0300Z 16.2N 84.0W 30 KT
12HR VT 07/1200Z 17.1N 84.2W 35 KT
24HR VT 08/0000Z 18.4N 84.8W 35 KT
36HR VT 08/1200Z 19.7N 85.5W 40 KT
48HR VT 09/0000Z 21.4N 86.5W 45 KT
72HR VT 10/0000Z 25.5N 88.0W 45 KT
96HR VT 11/0000Z 27.5N 87.0W 45 KT…EXTRATROPICAL
120HR VT 12/0000Z 26.5N 85.6W 35 KT…EXTRATROPICAL