SEVERE WEATHER THREAT: SLIGHT
TROPICAL STORM FORMATION: TROPICAL STORM DANNY
ALL forecasts contained on this site, are based on my analysis and knowledge of various forecast tools, including information contained in NHC products, and are not copies from any other entity.
*NOTE: In the TROPICAL STORM FORMATION line above, probabilities are for during the next 5 day period. My personal probability will be listed as either NONE, MONITORING or PROBABLE. This does not necessarily mean something will develop, but that certain forecast conditions are likely to be present, favoring development. Once NHC products become available, then the appropriate probability and percentage will be used.
Please refer to the link for the Storm Prediction Center in the box at the top of the page, just below the Hurricane Hunter graphics.
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Current Storm Total for 2015:
TOTAL STORMS: 4
INTENSE HURRICANES: 0
U.S. LANDFALLS: 2
StormW Seasonal Forecast:
TOTAL STORMS: 8
INTENSE HURRICANES: 1
Good day everyone!
Tropical Storm Danny continues to move to the west at around 12 mph. As of the 11:00 a.m. advisory from the NHC, the following information was available on Danny:
Location: 11.2°N 41.1°W
Moving: W at 12 mph
Min pressure: 1000 mb /29.53 in
Max sustained: 50 mph
The following maps are from HURREVAC, and are the same as the NHC tracking maps.
Satellite imagery this morning indicates DANNY is not as impressive as he appeared yesterday evening. The main factor for this, is the entertainment of some slightly drier air on the south and SE portion of the storm, as seen in close up water vapor satellite loop imagery. There is also noted some possible slight interaction and competition with convection to the east of DANNY.
Another slight mitigating factor is, earlier, the upper level anticyclone (clockwise flow) over DANNY was displaced somewhat to the west, possibly inducing a very slight tilt in the storm.
Based on analysis of the wind shear forecast maps, upper level winds are forecast to remain conducive for further slow development of DANNY. The GFS indicates keeping an upper level anticyclone over DANNY, for at least the next 5-6 days in the forecast period. This same time frame places the storm at or over the northern Leeward islands. Based on the premise of favorable upper level winds over the next 5-6 days, the only real inhibiting factor in DANNY strengthening would be dry air intrusion. However, satellite loop images would indicate the core of DANNY has become a little tighter. Close up water vapor imagery seems to indicate that the environment around DANNY is not too terribly dry, and loop imagery seems to indicate thunderstorm activity may be trying to wrap around the center from the NW. It is unknown at the moment whether this is a trend, or just intermittent. Given the tight core, DANNY could begin to mix out some of the dry air, as he approaches some higher OHC over the next 36-48 hours.
Based on the premise of the upper level wind forecast, and higher OHC, and the uncertainty of how much dry air may be entrained, I have to concur with the NHC intensity forecast for the next 5 days. The 12Z intensity forecast models have backed down somewhat on intensity as well.
NHC INTENSITY FORECAST
FORECAST POSITIONS AND MAX WINDS
INIT 19/1500Z 11.2N 41.1W 45 KT 50 MPH
12H 20/0000Z 11.4N 42.6W 50 KT 60 MPH
24H 20/1200Z 11.9N 44.2W 55 KT 65 MPH
36H 21/0000Z 12.4N 45.8W 60 KT 70 MPH
48H 21/1200Z 13.1N 47.5W 70 KT 80 MPH
72H 22/1200Z 14.4N 51.5W 80 KT 90 MPH
96H 23/1200Z 15.6N 56.2W 75 KT 85 MPH
120H 24/1200Z 16.6N 61.5W 70 KT 80 MPH
DANNY continues to move toward the west, however satellite loop images indicate more of a WNW motion over the past few hours, which would coincide more given the weakness in the subtropical ridge to the NW of the storm. Based on my analysis of forecast steering maps, DANNY should continue this motion during the next 48-72 hours. Thereafter, track will depend on two things…the strength of DANNY, and how fast ridging builds back in north of the storm. Based on a blend of the global models, consensus, and GFS Ensemble models, I have to agree with the NHC forecast track at the moment. This is based on the premise of DANNY following the intensity guidance, in being a weaker hurricane than originally anticipated. Should he strengthen more, he would have a tendency to follow a track possibly just skirting the northern Antilles.
All interests in the Windward and Leeward islands should closely monitor the progress of Danny during the next 5 days for any significant changes. Residents within the error cone should begin reviewing their Hurricane Preparedness plans. IF you do not have a plan, please visit my “links” section on the right hand side of the page. I will continue to monitor Danny during the next 72-96 hours for any significant forecast changes to the steering pattern and upper level pattern.
Have a blessed day!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST / SEVERE WEATHER SPECIALIST MEMBER WEST CENTRAL FLORIDA AMS