Bermuda Weather Service Forecast Discussion

For Sunday, February 17, 2019  18:00 UTC

FORECASTER - Gary Hall 

NOWCAST (Sunday evening through Sunday night)
Zonal flow is seen above a weak and disintegrating cold front to 
the immediate north of Bermuda. This is clearly depicted on the latest 
ASCAT pass as most cyclonic turning is to the north, with less convergence 
upstream. Radar shows what few isolated showers there are to also 
dissolve as they approach the Island, while satellite has mainly 
just a few fingers of stratocumulus/cumulus bands with very little 
vertical growth. This is a result of being rather stable, even with 
the moderate southwesterly winds ahead of the boundary. But, with 
virtually no cold air aloft the airmass tends to not have any punch 
to it, or significant shower activity. We have seen periodic wind 
speed peaks into the low 20ís thus a Small Craft Warning was in effect 
for the afternoon but will allowed to expire heading into this evening 
as all indications are for the winds to drop off to ~ 10 knots along 
and behind the weak boundary. Both the GFS and UKMO show a weak surface 
ridge building in tonight, then moving eastward by morning with southwesterly 
winds increasing once again. Seas are analyzed as moderate and will 
abate slightly overnight. Meanwhile, given the westerly fetch the 
overnight low will only dip to the mid 60ís.

AVIATION: VFR no hazards. TXKF winds favor runway 30 as we are west-northwesterly 
this evening then back slightly towards dawn, while staying mainly 
in the 8-12 knot range. For current airfield information please visit: 
http://www.weather.bm/Aviation

SHORT TERM FORECAST (Monday-Tuesday): 
Forecast vertical profiles and meteograms point to a dry day ahead 
on Monday. No model discrepancies are noted as output shows a resurgent 
southwesterly wind once again that will warrant a Small Craft Warning 
by mid-day at the latest and persist until the next cold front arrives 
early Tuesday morning, then veer northwesterly remaining moderate 
to strong thereafter. This front has a bit more push to it than the 
one today and will be primarily felt via colder temperatures and 
strong winds developing from the north on Tuesday. There are not 
any significant rainfall expectations aside from a passing shower 
just after daybreak Tuesday, and then we contend with increasing 
northwesterly winds and seas building to rough Tuesday afternoon 
and into the night. Surface pressure will be on the rise as the cold 
high to the northwest sends a ridge to Bermuda, while the winds continue 
to veer northerly Tuesday night with the 850MB temperature expected 
to dip to +05C, or a surface temperature in the upper 50ís by Wednesday 
morning. Cold air ocean stratocumulus is likely to be delayed behind 
the front Tuesday morning for some 12 hours so we may not get the 
extensive cloud cover until Tuesday night with the cooling conditions. 


LONG TERM FORECAST: (Wednesday-Thursday):
Surface pressure continues to rise on Wednesday which is likely 
to reach 1030MB by Wednesday evening as the high centre passes nearby. 
Skies will remain rather cloudy however in the cooler air field on 
Wednesday, but then decrease in coverage on Thursday as warm southwesterlies 
return. Temperatures will obviously be on the rise Thursday under 
increased sunshine and southwest winds surpassing 20 knots by Thursday 
evening, thus a Small Craft Warning will be necessary from this point 
forward. Seas will be building as well, though not quite to rough. 
Expect the afternoon high on Thursday to surpass 70F under this increasingly 
stable scenario. Confidence is high through the long range as all 
models are settling on a similar solution.