Good day everyone!
Tropical Storm Cristobal continues a very slow motion to the north, and has strengthened since yesterday evening. As of the 8:00 P.M. Intermediate advisory from the NHC, the following information was available on Cristobal:
Location: 24.6°N 73.1°W
Moving: N at 3 mph
Min pressure: 994 mb / 29.35 in
Max sustained: 60 mph
Cristobal is moving very slowly to the north, and is following a weakness in the subtropical ridge created by a mid to upper level trof digging between the U.S. east coast and Bermuda.
Based on my analysis of current and forecast steering layers maps, and water vapor satellite loop imagery, I concur with the NHC forecast track, and is inline with Dynamic Model Guidance. Track forecast should remain pretty straight forward, unless some whacky change occurs in the steering pattern over the next 48 hours. The cyclone should continue a very slow motion for at least the next 12 – 18 hours, before the approaching trof turns Cristobal more toward the NE.
Cristobal is currently being sheared from the NW, and is evident by the center of circulation being exposed in satellite loop images, with the heavy convection off the the SE of the center.
Based on my analysis of the zonal wind shear forecast from the GFS, upper level winds are forecast to subside within the next 12 – 18 hours, with conditions becoming more conducive for further development by 24 hours. s the shear values relax, gradual strengthening should occur.
Based on these circumstances, I concur with the NHC intensity forecast.
NHC INTENSITY FORECAST
FORECAST POSITIONS AND MAX WINDS
INIT 25/0900Z 24.5N 72.8W 45 KT 50 MPH
12H 25/1800Z 25.2N 72.5W 50 KT 60 MPH
24H 26/0600Z 26.8N 71.7W 55 KT 65 MPH
36H 26/1800Z 29.3N 70.9W 60 KT 70 MPH
48H 27/0600Z 31.5N 70.4W 65 KT 75 MPH
72H 28/0600Z 35.2N 66.0W 65 KT 75 MPH
96H 29/0600Z 40.5N 53.5W 65 KT 75 MPH
120H 30/0600Z 48.5N 41.0W 60 KT 70 MPH…POST-TROP/EXTRATROP
Tropical Disturbance INVEST 97L continues to move westward in the CATL this morning. As of the 06Z ATCF tracking information, the following was available on INVEST 97L:
The disturbance continues to move west, around the southern periphery of the subtropical ridge. I expect this motion to continue during the next 48 to 60 hours. Based on the steering layers forecast maps, valid for 12Z this morning, a more WNW motion should begin approximately thereafter.
Analysis of the current wind shear products indicates upper level winds are not conducive at this time…however analysis of the zonal wind shear forecast currently indicates upper level wind could become more conducive beginning in about 90 hours, or as it approaches the Lesser Antilles. Water vapor imagery indicates dry air is surrounding this disturbance, and the possibility exists it may not survive. There is one model however that does eventually develop this later in the period which is the CMC. Regardless, I will continue to monitor this as it continues to cross the CATL.
Another vigorous wave ids located over central Africa at the moment, and may have to be monitored closely, as upper level winds are forecast to be conducive for development as soon as it hits the water. However, should it come off too high in latitude, forecast steering maps, and some f the Global Models indicate it could be a very early re-curvature.
I will not have another update until tomorrow morning.
Have a blessed day!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST / SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS
OFFICIAL SKYWARN SPOTTER (ADVANCED)