Bermuda Weather Service Forecast Discussion

For Thursday, September 29, 2022  21:00 UTC

FORECASTER - Alex Young 

NOWCAST: (This evening and tonight)
The day was generally sunny with few cumulus cloud ranging between 
1,000-2,000ft and scattered to broken thin cirrus cloud near 30,000ft. 
No showers were observed over the island while isolated showers were 
observed just east of the marine area during the early morning. Latest 
satellite imagery shows a similar picture with partly cloudy skies 
being observed with little cloud cover upstream. Latest radar imagery 
shows no echo activity. Latest surface analysis shows a ridge of 
high pressure extending from the northeast over the area, tropical 
storm Ian east of northeastern Florida and an inverted trough to 
the distant southeast. Water Vapour imagery shows upper ridging extending 
over the region with upper lows and upper troughing off to the distant 
southeast, west-southwest and northwest respectively. This has initialized 
well with the global models and there is high confidence in the synoptic 
pattern. There is good consensus between the global models that anticyclonic 
flow within the upper ridge remains dominant overnight. Global models 
also suggest that the ridge of high pressure remains dominant as 
well which will maintain dry weather and partly cloudy skies. However, 
nocturnal cooling and weak low-level convergence may aid the odd 
pre-dawn shower forming as high cloud thickens at times. Winds at 
our AWOS stations and the airport were southeasterly to east-southeasterly 
during the day whilst remaining near 8-12 knots. Currently winds 
have changed little and have initialized well with the global models. 
Expect the wind to back more easterly this evening with no chance 
in intensity. Latest OPC analysis has seas near 4ft which has also 
initialized well with the global models. Expect slight to borderline 
moderate seas to continue overnight.

Warning Strategy: No watches or warnings are in effect for this 
evening and tonight.

AVIATION:
Runway 12 is expected to be the active runway overnight as an easterly 
to east-southeasterly wind ranging between 6-12 knots persists. VFR 
conditions and no aviation hazards are anticipated.  For more information 
visit: http://weather.bm/aviation/


SHORT TERM FORECAST (Friday through Saturday)
For the short term period, an upper ridge will linger about the 
area re-orientating through into the weekend. Near the surface, weak 
troughing will gradually drift into the area from the east. This 
will bring overnight increases to cloud cover and a few showers into 
Saturday. Global models do diverge regarding the amount of cloud 
cover and coverage of showers. The presently exists only the slight 
potential for showers with the highest likelihood overnight between 
the two days and towards Saturday evening. Wind data within the suite 
maintains the light to moderate flow but backs speeds towards the 
east. Then, on Saturday, winds veer and tend towards the southeast 
once again. Concerning seas, the UK and GFS wave models both increase 
states slightly towards the 3-5 foot range.

Warning Strategy: No watches or warnings are currently anticipated 
for the short-term period.

LONG TERM FORECAST (Sunday through Monday)
On Sunday, a trough will continue to move in from the southeast 
and east. Meanwhile, the remains of the former Hurricane/Tropical 
Storm Ian will move off the east coast of the US and near from the 
area. A trough extending from the remnant low through the south will 
gradually approach. This pattern is poised to interrupt the largely 
bright and dry conditions from Sunday night into Monday. Bright daytime 
skies are anticipated through Sunday as winds tend to settle out 
of the south to south-southeast. Speeds within the suite increase 
nearing the mid-moderate range. Then overnight and into Monday, expect 
the moistening of conditions as the trough from the east and trough 
from the west converge overhead. This will lead to an increase of 
cloud cover and potential for showers. QPFs increase within the suite 
towards the 5-10 mm range. A showery day becomes likely on Monday. 
Indices increase from Monday becoming favorable along with the upper 
support as an upper trough develops and deepens to our west. 
Wind data within the NWP increases through Monday nearing the upper 
bounds of the moderate criteria towards the 14-18 knot range. The 
UK and GFS wave models increase sea states towards the 4-7-foot range. 


Warning Strategy: No watches or warnings are currently anticipated 
for the long-term period. However,  there exists the chance of a 
Thunderstorm Advisory for Monday, albeit low at the moment but this 
could increase in the coming days, especially as the remnant tropical 
moisture begins to move in.

TROPICAL:  Please refer to the latest Tropical Weather Outlook (TWO) 
courtesy of the National Hurricane Center (NHC) for more details 
via https://www.nhc.noaa.gov/