TROPICAL CYCLONE FORMATION: HURRICANE GASTON / T.S. HERMINE /T.D. 8 /
Disclaimer: This site is not affiliated with the National Hurricane Center, Storm Prediction Center, or National Weather Service. ALL forecasts herein are the result of my analysis, and I am solely responsible for the content.
(T. F. “Storm” Walsh III)
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CURRENT 2016 ATLANTIC TROPICAL CYCLONE TOTALS:
TOTAL STORMS: 8
MAJOR HURRICANES: 1
StormW’s Seasonal Hurricane Forecast:
TOTAL STORMS: 13-15
INTENSE HURRICANES: 3-4
THE FOLLOWING IS A QUICK UPDATE:
I am analyzing things to put in the 5:00 p.m. update. However, T.D. 9 was found to have TS force winds, and has been designated Tropical Storm Hermine. As of 2:00 p.m. EDT on the intermediate advisory, the following information was available on HERMINE:
1:00 PM CDT Wed Aug 31
Location: 24.7°N 88.0°W
Moving: N at 2 mph
Min pressure: 1000 mb / 29.53 in
Max sustained: 40 mph
Dynamic model guidance has once again shifted slightly left, or to the west, which would now bring Landfall to Apalachicola. This may fluctuate, depending on how strong the storm becomes over the next 12-24 hours. The storm is beginning to move north in response to a weakness in the ridge over the Carolinas/GA area, and in response to a trof far north, digging down over the NW Great Lakes region. The shift left appears to be in response to the weakening ridge over the central plains area which has been moving slowly, This combination is making the storm move very slow northward, in very weak steering currents. There however is no change in the forecast track thinking of this eventually turning NNE and NE within the next 24 hours. Analysis of updated steering forecast maps did not indicate any change as of yet to the overall steering pattern.
The forecast is still for HERMINE to strengthen further prior to landfall. The updated GFS and ECMWF models still indicate an upper level anticyclone, which favors strengthening, to remain over HERMINE until landfall.
Given the shift left in guidance, I do not know at this time if the Tropical Storm Warning and Hurricane Watch areas will be changed as far as being moved further north away from the Anclote river area. This will have to be seen in the NHC 5:00 P.M. update.
I will try to have this information available tonight.
Good day everyone!
A TROPICAL STORM WARNING and HURRICANE WATCH REMAIN IN EFFECT FOR A GOOD PORTION OF THE FLORIDA WEST COAST
TROPICAL STORM WARNING: An announcement that tropical storm conditions (sustained winds of 39 to 73 mph) are expected somewhere within the specified area within 36 hours in association with a tropical, subtropical, or post-tropical cyclone.
HURRICANE WATCH: An announcement that hurricane conditions (sustained winds of 74 mph or higher) are possible within the specified area in association with a tropical, subtropical, or post-tropical cyclone. Because hurricane preparedness activities become difficult once winds reach tropical storm force, the hurricane watch is issued 48 hours in advance of the anticipated onset of tropical-storm-force winds. During a Watch, prepare your home and review your plan for evacuation in case warnings are issued. Listen closely to instructions from local officials.
A Hurricane Watch will sometimes include conditions where 74 mph + winds may not be experienced, however strong enough to push in storm surge, very heavy rainfall, storm and high wind gusts. In the situation with Tropical Depression NINE, a Hurricane Watch has been issued as the slim possibility does exist that the depression could attain hurricane status briefly and close to landfall.
As of the 8:00 a.m. EDT intermediate advisory form the NHC, the following information was available on Tropical Depression NINE:
7:00 AM CDT Wed Aug 31
Location: 24.6°N 88.1°W
Moving: N at 2 mph
Min pressure: 1001 mb / 29.56 in
Max sustained: 35 mph
Recent satellite loop imagery indicates that the depression continues to become slightly better organized, with convection beginning to build nicely over the Low Level Circulation (LLC). The central pressure has fallen to 1001 mb…down from 1004 mb from 3 hours ago. This may indicate the depression could very well be close to Tropical Storm status.
I have no change in my thinking in forecast intensity, and the depression should become a Tropical Storm soon. I do concur with the NHC, and we should see more of a steady strengthening as this begins to move off toward the NE. I agree currently with the NHC intensity forecast, however, based on a couple of items per my analysis this morning, I cannot fully rule out the possibility of a stronger Tropical Storm, or a very breif run for minimal CAT 1 hurricane just very prior to landfall. The depression is currently under some fairly favorable conditions, save some slight wind shear north of it. The recent upper level wind product indicates an excellent outflow pattern over the system. The depression has plenty of TPW to work with, so as it nears the peninsula of Florida, it will drag in a lot of moisture from the GOMEX, hence heavy rainfall. Last, it will be moving over some higher Ocean Heat Content (OHC) as it nears the Big Bend region. If the upper pattern remains favorable, these conditions could allow for a minimal CAT1 hurricane very close to the coast before making landfall.
NHC INTENSITY FORECAST
FORECAST POSITIONS AND MAX WINDS INIT 31/0900Z 24.5N 88.1W 30 KT 35 MPH 12H 31/1800Z 25.4N 87.8W 40 KT 45 MPH
24H 01/0600Z 26.9N 86.9W 45 KT 50 MPH
36H 01/1800Z 28.4N 85.6W 55 KT 65 MPH
48H 02/0600Z 30.3N 83.6W 55 KT 65 MPH…INLAND
72H 03/0600Z 34.2N 76.8W 60 KT 70 MPH…OVER WATER
96H 04/0600Z 37.0N 70.2W 60 KT 70 MPH
120H 05/0600Z 39.0N 68.0W 55 KT 65 MPH…POST-TROP/EXTRATROP
The depression has slowed in forward speed, and is almost stalled. This is usually a good sign that the track may begin to change soon. I have no change in the forecast track logic, and the system should begin to move more toward the NNE or NE sometime later today. Current and forecast steering indicate what I have been preaching over the past 3 days….the ridge that was situated over the Mid Atlantic states 3-4 days ago, has shifted west and weakened, and a weakness in the sup-tropical ridge is now present near the Carolinas (you’ll note that weakness creating an upward bend in the steering over the depression). Forecast steering still indicates the combination of a trof coming down from the north, and the western periphery of the western subtropical ridge center, should become the dominant flow probably by late this evening into tomorrow, and is reflected in the NHC forecast track and dynamic model guidance. Based on this, if nothing changes, the west side of the system should just brush the Apalachicola area and should make landfall between Crawfordville and Perry.
Albeit the possibility of residents south of the Big Bend area, outside of the wind radius may not experience hurricane force winds, the NHC and NWS HAS ISSUED A HURRICANE WATCH and TROPICAL STORM WARNING.
Residents along the Florida west coast within the watch and warning areas should be making preparations, per your local NWS office. On the right side of this page, under LINKS, I have links for various preparedness guides.
The main threat from this system appears to be excessive amounts of rain, and the potential for flooding and flash flooding, as well as isolated tornadoes.
The following graphics represent the potential hazards from this system
Residents should monitor their local NWS office for statements and/or warnings associated with this system. Residents along the coast should remain away from beaches and out of the water due to the possibility of minor coastal flooding and rip currents.
The following are links to local NWS STATEMENTS.
The following map is linked for you to click on your area of interest. It will take you to your local NWS office for updated statements and warnings.
PLEASE BE SMART…PLEASE BE SAFE!
I may have another update late this afternoon/early evening.
Have a blessed day!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST /SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS