Bermuda Weather Service Forecast Discussion

For Wednesday, August 21, 2019  20:00 UTC

FORECASTER - Ken Smith 

Bermuda Weather Service Forecast Discussion
For PM Wednesday, 14 August 2019
Forecaster:  KS

NOWCAST (Tonight)
Satellite imagery clearly shows the ridge axis has now drifted to 
our north and this is confirmed by the latest ASCAT analysis.  A 
broad, disorganized area of unsettled weather to our south is connected 
with an ill-defined trough approaching from the southeast.  RADAR 
is clear all quadrants inside 25NM.  There are isolated showers between 
25-50NM in the southeastern quadrant moving this direction, and further 
activity 100NM plus south and southeast.  There have also been isolated 
spherics returns with the closer activity.  Our current sky condition 
is broken.  Winds are light southeasterly.  The latest north Atlantic 
surface analysis from the Ocean Prediction Centre shows seas in our 
area 3-4 feet which initializes well with the UK wave model.

All global models are in generally good agreement.  The ridge axis 
now lying east to west near to our north will persist.  This may 
serve to weaken any approaching shower or thunderstorm activity, 
though that cannot be ruled out entirely.  Stability indices become 
more favourable for potential thunder by after midnight.  This will 
also maintain mainly light southeasterly winds through tonight, though 
winds may gust to strong at times near showers and/or thunderstorms. 
 Seas will remain smooth to slight.

There are no watches or warnings at this time, however, a Thunderstorm 
Advisory could be issued with short notice as conditions warrant 
 more likely after midnight.

AVIATION  Predominantly VFR conditions are expected for the next 
24 hours, however, MVFR conditions are possible after 22/00Z with 
tempo SHRA, and after 22/03Z with tempo TSRA, until 22/12Z.

SHORT TERM FORECAST (Thursday & Friday)
High pressure will persist to our east throughout Thursday and Friday, 
and the ridge axis will once again shift to our south on Friday. 
 Thursday and Friday are both expected to see scattered showers. 
 Stability indices a favourable for thunder both days, with the highest 
probability being Thursday morning.  Winds will be light southeasterly 
on Thursday, likely to gust to strong near showers and/or thunderstorms. 
 On Friday light south-southeasterly winds will slowly veer southwesterly. 
 Seas will remain smooth to slight through Friday.

A Thunderstorm Advisory could become necessary at any time Thursday 
and/or Friday as conditions warrant, with the most likely period 
being Thursday morning.  Otherwise, no watches or warnings are expected.

LONG TERM FORECAST (Saturday & Sunday)
The Bermuda-Azores high will maintain a ridge to our south Saturday 
and Sunday.  This will maintain light to moderate southwesterly winds 
both days.  As troughs continue to rotate around the western flank 
of the ridge, Saturday and Sunday can both expect scattered showers 
and a chance of thunder.  Seas will remain smooth to slight through 
Sunday.

TROPICAL INFORMATION
NHC is now issuing forecast advisories on Tropical Storm Chantal. 
 TS Chantal is past its closest point of approach to Bermuda and 
is not a threat.  For further information and tracking charts please 
see www.weather.bm.

An area of disturbed weather extends over the Central and Northwest
Bahamas and the adjacent waters.  Some slow development of this
system is possible over the next several days as it moves toward 
the
Florida peninsula and then the southeastern United States.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.