10/5/05 FCST: Tropical Storm Tammy (dissipated)

[Sam Sagnella]

Tropical Storm Tammy officially formed just off the east coast of FL earlier this morning. Tammy consists of a large blob of deep convection near or just to the NE of the center of circulation, with additional strong thunderstorms extending well to the N and E.

21L should be steered to the NNW before making landfall along the NE FL or SE GA coastlines later today or tonight. As the NHC notes in the 1130z advisory, the angle of approach drastically increases the uncertainty in any particular landfall point as the storm should be moving nearly parallel to the cost for the majority of the day. I am quite impressed with the AF-MM5's performance in regards to Tammy -- for days the model has been hinting at development from 92L and was one of only a couple to consistently suggest that tropical development would occur E of the FL peninsula.

As far as intensity is concerned, Tammy has only about 12-18 hours (at most) to strengthen before the center crosses the coast. Because of this limited time over water, and strong persistant WNW/NWly shear, this cyclones maximum intensity will very likely not exceed the 45-50kt range, if that.

With Tammy, *wind impact does not appear to be the main threat* and this could be a rather prolific rainfall producer over the SE part of the country -- widespread flooding is a definite possibility.

 

[cdcollura]

Buoy 41009 Gets Center Of Tammy

Good morning,

The center of TS Tammy passed over NOAA buoy 41009 20 miles to the east of Cape Canaveral, Florida. What is very interesting is the wind and pressure readings at roughly 8:50 AM (the center of the low, about 1004 mb, or 29.64", passed from south to north over the buoy). Also note the winds were originally east with falling pressure, then became extremely light NNW, then resumed from the SSW with rising pressure.

The NHC discussion also reflects this, as Tammy is moving NNW / N at less than 15 MPH.

000
WTNT41 KNHC 051433
TCDAT1
TROPICAL STORM TAMMY DISCUSSION NUMBER 2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM EDT WED OCT 05 2005

AT 13Z THE CENTER OF TAMMY PASSED OVER NOAA BUOY 41009...WHICH
REPORTED A PRESSURE JUST UNDER 1004 MB. OBSERVATIONS FROM THE BUOY
AND NWS RADAR INDICATE THAT TAMMY IS NOW MOVING NORTHWARD AT ABOUT
12 KT. THIS RIGHTWARD DEFLECTION OF THE TRACK MAY BE A RESPONSE TO
THE ASYMMETRIC DISTRIBUTION OF CONVECTION...WHICH REMAINS TO THE
NORTH AND EAST OF THE CENTER. TAMMY IS LOCATED BETWEEN A MID- TO
UPPER-LEVEL LOW OVER THE NORTHEASTERN GULF OF MEXICO AND A
DEEP-LAYER RIDGE OVER THE MID-ATLANTIC STATES. THIS SYNOPTIC
PATTERN IS EXPECTED TO TURN TAMMY TO THE NORTHWEST OVER THE NEXT 12
TO 24 HOURS. THE MAIN QUESTION IS HOW MUCH THE CENTER WILL JUMP OR
REFORM TO THE RIGHT IN RESPONSE TO THE CONVECTION. THE 00Z
CANADIAN MODEL SEEMS TO HAVE HAD THE BEST HANDLE ON TAMMY
OVERNIGHT...AND I AM GIVING THIS MODEL MORE THAN THE USUAL AMOUNT
OF WEIGHT THIS MORNING. THE OFFICIAL FORECAST IS ADJUSTED A LITTLE
TO THE RIGHT OF THE PREVIOUS ADVISORY. BECAUSE TAMMY IS MOVING
ROUGHLY PARALLEL TO THE FLORIDA COAST...AND BECAUSE MOST OF THE
WEATHER ASSOCIATED WITH TAMMY IS WELL-REMOVED FROM THE CENTER...THE
PRECISE LOCATION AND TIMING OF THE LANDFALL OF THE CENTER IS OF
RELATIVELY LITTLE IMPORTANCE.

Chris C - KG4PJN

 

[Sam Sagnella]

This is interesting - the recon flight currently investigating Tammy is reporting 53kt FL winds as of 1727z near 31N 78.8W. Since this is located underneath an area of VERY deep convection...I wouldn't be surprised if winds of nearly this magnitude are occurring at the surface.

18z update should show a marked increase in winds -- maybe to 50kt?