TROPICAL STORM FORMATION: GRACE
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*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.
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Current Storm Total for 2015:
TOTAL STORMS: 7
INTENSE HURRICANES: 1
U.S. LANDFALLS: 2
StormW’s Seasonal Forecast:
TOTAL STORMS: 8
INTENSE HURRICANES: 1
5:15 P.M. EDT: Edit to note new area of disturbed weather in the GOMEX. NHC designates a LOW (10%) probability for cyclone development
Good day everyone!
GRACE continues to move toward the west, at a little quicker pace of 17 mph. As of the 11:00 a.m. advisory from the NHC, the following information was available on GRACE:
11:00 AM AST Mon Sep 7
Location: 13.7°N 35.9°W
Moving: W at 17 mph
Min pressure: 1004 mb/29.65 in
Max sustained: 45 mph
HURREVAC NHC FORECAST TRACK
Satellite imagery this morning indicates GRACE has become less organized and the structure deteriorating. Analysis of the current wind shear map, along with water vapor loop imagery, indicates GRACE is now undergoing the wind shear increase that has been called for, as well as an increase in dry air in her surrounding environment. In fact, water vapor loop imagery indicates dry air is impinging heaviest on her western side. The current wind shear forecast indicates upper level winds to increase even further over the next 48 hours or so, and remain in place through the 5 day forecast period. Based on this, I concur with the NHC forecast intensity at the moment. However, based on analysis of satellite loop imagery, and the increase in drier air, combined with the faster forward motion, I believe that GRACE could begin to weaken a little sooner than forecast. I do agree in that she will eventually become a remnant low, and dissipate into an open wave.
NHC INTENSITY FORECAST
INIT 07/1500Z 13.7N 35.9W 40 KT 45 MPH
12H 08/0000Z 13.9N 38.1W 40 KT 45 MPH
24H 08/1200Z 14.1N 41.5W 40 KT 45 MPH
36H 09/0000Z 14.5N 45.0W 40 KT 45 MPH
48H 09/1200Z 14.9N 48.1W 40 KT 45 MPH
72H 10/1200Z 15.5N 54.5W 35 KT 40 MPH
96H 11/1200Z 16.3N 61.0W 30 KT 35 MPH
120H 12/1200Z 17.0N 66.0W 25 KT 30 MPH…POST-TROP/REMNT LOW
Based on the negative forecast parameters, and possible interaction with land masses in the northern Caribbean, I am not really looking for any regeneration as she traverses the Caribbean. I will continue to monitor the system however, should conditions change…albeit this appears to be relatively slim.
GRACE continues to move toward a westerly motion (north of due west). Based on the current steering layers forecast maps, I expect this motion to continue during the next 72-96 hours, with more of a WNW motion as a remnant low as it comes closer toward a weakness in the subtropical ridge. This coincides with the NHC forecast track, and is inline with the tightly clustered dynamic model track guidance.
ATCF 12Z DYNAMIC MODEL GUIDANCE AND CONSENSUS
Elsewhere, I am monitoring a tropical wave over the extreme western portion of the African continent. Albeit upper level winds are conducive at the moment, they may become only marginal in a few days. I am not too impressed with the structure of this feature at the moment, and mid level water vapor images indicate the surrounding environment may be a little drier than what GRACE experienced as she moved off Africa. I will continue to monitor the area for any significant changes.
There is one more wave at the moment, located over central Africa. Be interesting to see if this makes it or not.
Analysis of the global models this morning indicate “hints” of possible mischief in the extreme western GOMEX in about 6-7 days. The ECMWF indicates development of a tropical storm, and the GFS a weak, closed low along the TX coast. The CMC had previously indicated something in the Gulf, but has since dropped the solution. I am not concerned as of yet, until I can analyze further model runs for consistency and agreement.
Elsewhere, Tropical Storm formation is not expected during the next 5-7 days.
Have a blessed day!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST /
SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS