Bermuda Weather Service Forecast Discussion

For Friday, December 01, 2023  22:00 UTC

FORECASTER - Kimberley Zuill 

NOWCAST: This Evening through Tonight
Although high pressure ridging remained in charge today, there was 
a small area of SC that just wouldn’t burn off or drift away while 
Ci streamed overhead. Light N winds veered to the NE early morning 
and have gradually veered to become more ENE. Through tonight they 
will continue to gradually veer and the ridging lifts away to the 
NE. Models indicate that skies will become partly cloudy at times. 
In the cool air flow, temperatures struggled to rise very much today 
reaching the highest temp of 69F around noon before cloud cover moderated 
it. The humidity remained comfortably in the 60’s making today feel 
cool, cloudy and crisp.  OPC pegs our offshore seas around 4-5ft, 
which aligns well with global wave models. Seas will continue to 
ease, becoming mainly slight. No watches/warnings are expected.

AVIATION: VFR conditions RWY12 with ENE 05-08kts winds gradually 
veering ESE.  No hazards expected. For current airfield information 
please visit: 

SHORT TERM FORECAST: Saturday through Sunday
Upper ridging amplifies over us through Saturday while troughing 
advances from the west. 
A ridge of high pressure on the surface stretches out beyond Bermuda 
past Florida and into the Gulf of Mexico. As it weakens later on 
Sunday light SE wind gradually veer SW and increase moderate to strong 
during Sunday evening. The veering flow helps further WAA to develop, 
with temperatures recovering to near average. Provided the cloud 
that lingered nearby today scoots away, Saturday should see plenty 
of sunshine then clouds thicken on Sunday as per forecast vertical 
profiles, and a couple of pre-frontal/convergent showers are expected 
to develop by Sunday evening. Slight seas gradually build slight 
to moderate. 
WARNINGS: A small craft warning is valid for late Sunday evening 
through the night.

LONG TERM FORECAST: Monday through Tuesday
Deep upper troughing moves into the area during the period, with 
an upper trough axis passing by early on Tuesday morning. This corresponds 
to a deepening area of low pressure to the distant N which gradually 
steers a front across the local area. Winds ahead of the front will 
increase and based on the last couple of model runs, the forecast 
has been nudged up to 20-30 gusting 40 knots in the early hours of 
Tuesday, these higher gusts are expected in and around showers especially. 
There is still some discrepancy as to how quickly the winds will 
veer NW, as some models indicate a slight sympathetic ridging followed 
by a secondary trough. Others have a broader boundary and some even 
suggest fragmentation to our south (the creation of the “Bermuda 
Gap”!) regardless at some point during mid Tuesday meaning winds 
will veer NW and ease to moderate. Showers are expected to break 
out later Monday, mainly overnight into Tuesday morning, when they 
clear out rapidly with FROPA. QPFs are quite wide ranging as some 
of the model guidance brings deep convection overhead. However, a 
good middle ground appears to be around 0.5” for the moment. Instability 
indices show a marginal risk of thunder Monday night. Although this 
is not yet stated in the detailed forecast products, this will need 
to be monitored closely with further model guidance as not only will 
it need to be incorporated into the forecast, but a thunderstorm 
advisory may also be required. Temperatures ahead of the front may 
peak as high as 24C/75F, before cooling off thereafter. All models 
indicate a rapid transition of a small region of high pressure during 
the remainder of Tuesday and overnight, however the synoptic pattern 
becomes quite messy for Wednesday as subsequent forecasts will detail. 
Seas build moderate to rough on Monday and only begin to abate later 
Tuesday, but only briefly. 
WARNINGS: A small craft warning will be needed for the long term