Bermuda Weather Service Forecast Discussion

For Thursday, September 28, 2023  19:00 UTC

FORECASTER - Kimberley Zuill 

NOWCAST: This Evening through Tonight
Another fair day while weak surface high pressure meanders nearby 
keeping light winds NW until late afternoon when they backed W. Overnight 
as the high drifts closer, light local winds will become variable 
in direction then settle to the SE towards dawn. For the most part, 
conditions will remain dry with a few cumulous clouds and the thin 
veil of cirrus thickening at times into a broken layer. RADAR has 
shown showers to our distant north, well beyond the marine area, 
associated with the nearly stationary boundary located there. In 
the upper levels we remain between anticyclonic flow to our SE and 
broad troughing to our distant north. Latest OPC has seas near 5-7ft 
which is in agreement with model initialization. 
WARNINGS: No watches or warnings are in effect.

AVIATION: RWY30 W wind 5-8 knots become variable in direction then 
settled SE by dawn. VFR conditions and no aviation hazards are anticipated. 
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SHORT TERM FORECAST: Friday through Saturday
By Friday upper troughing to the north sinks further into our area, 
while on the surface, a low becomes more organized to our northwest 
and with the south through SW flow bands of convergence develop ahead 
of the main front, which may bring a few showers overnight on Friday 
with the main front reserved for Saturday morning. Temperatures rebound 
on Friday into Saturday within the S through SW flow and the humidity 
rises in advance of the first of a series of weak troughs approaching 
from the W through NW. Seas of 5-7ft will decrease slightly Friday 
night to become 5-6ft. 
WARNINGS: No watches or warnings are currently anticipated for the 
short-term period. 

LONG TERM FORECAST: Sunday through Monday
In the early hours of Sunday, in the pre-frontal flow and within 
any showers we may experience occasional gusty conditions. The UK 
solution is still the more robust and indicates clusters of heavier 
showers with indices supporting possible thunderstorms, whereas the 
GFS has a more fragmented and shallow boundary. The timing of the 
wind shift and cessation of rainfall is also delayed in the UK solution, 
however overnight there will be less shower activity and eased westerly 
winds that may fluctuate either side of west at times. Confidence 
is low as the models keep fluctuating the location and intensity 
of showers, as well as if the low in our region will be a single 
centre or double or triple! The overall pattern places us in the 
middle with 3-4 separate large scale surface lows looming on our 
distant horizons, in all four corners of the compass! Moderate winds 
fluctuate either side of west during Monday but confidence is low, 
based on the uncertainty of if there will be a low centered to our 
near north (UK solution) or to our NE (GFS). All models indicate 
light precipitation in and around our area, possibly forming a secondary 
trough, but we shall have to see the development and positioning 
of the low in order to have higher confidence on those particulars. 
 By Monday as the low tends to start to lift out of our area but 
light precipitation is scattered around, generally it looks like 
there will be a drying trend and winds look to finally veer NW later 
on Monday. Temperatures have been forecast as such, and therefore 
we may have a brief “fall feel” to the air by Monday evening. Slight 
to moderate seas persist. 
WARNINGS: No watches or warnings are currently anticipated for the 
long-term period, though if the UK solution trends towards reality 
then a thunderstorm advisory may be issued for Sunday morning/early 

TROPICAL:  BWS are issuing TUBs on TS Philippe and TS Rina (which 
formed at noon). Please refer to the latest Tropical Weather Outlook 
(TWO) courtesy of the National Hurricane Center (NHC) for more details