Bermuda Weather Service Forecast Discussion

For Monday, December 06, 2021  09:00 UTC

FORECASTER - Troy Anderson 

Nowcast (Monday)
Mostly cloudy skies dominated the overnight period as the centre 
of a nearby ridge of high pressure gradually drifted off to the northeast. 
Light easterly winds veered towards the southeast and increased becoming 
moderate. The latest GOES 16 IR satellite imagery shows Bermuda under 
extensive upper cloud cover continuing to spill over from the northwest. 


The latest RADAR imagery remains mainly clear and echo-free. In 
the upper level analysis, Bermuda begins the period under the influence 
of a ridge stretching up into the area from the south. An upper trough 
will begin to move over CONUS from the northwest. The latest surface 
analysis puts Bermuda under high pressure ridging with a centre to 
our nearby north. A frontal boundary remains draped across the Atlantic 
to our distant northwest through northeast. Expect the gradual drift 
of the high pressure ridge to the northeast transitioning Bermuda 
to its southwestern flank. This pattern will hold the settled regime 
through the day with local pressures remaining near 1024 hPa. Global 
models continue to have a relatively decent handle on the synoptic 
pattern. Expect another dry day under the domination of the high 
with scattered cloud cover.

Model data continues to bring cloud cover into the area from the 
southeast around the edges of the high. Wind data within the suite 
slowly increases speeds through the day remaining moderate near 10-15 
knots. Directionally, expect the settling of winds southeasterly. 
The latest OPC wave analysis maintains 5- foot seas in our area with 
the expectation to remain moderate. MOS and other temperature data 
increase temperatures towards 74F and with the thin upper level cloud 
cover, veering winds, and increase of moisture this will likely be 
the case +/- 1 or 2 degrees. No watches or warnings are anticipated 
during this period. Confidence for the nowcast period remains moderate.

Aviation: VFR conditions continue through the period at TXKF with 
light to moderate winds near 08-14 knots from 130 degrees. No significant 
weather hazards are expected through the period. For more information 
please see www.weather.bm/aviation. 

Short-Term (Tuesday- Wednesday) 
On Tuesday, moisture is drawn up from the south into our area associated 
with weak linger troughing. Meanwhile, a frontal system will advance 
from the west before stalling nearby. Global models reorientate the 
high pressure ridge moving the centre of the ridge to the northeast. 
Early on Tuesday, cloud cover and a few showers develop before clearing 
through the day and returning through the night. By Wednesday, a 
prefrontal trough and frontal boundary will remain on our doorstep 
before gradually drifting overhead. The NWP suite fragments the feature 
over the area with the moisture splitting to the north and south. 
The decayed and fragmented boundary will then linger to our southeast 
through the period. A few showers are anticipated through Tuesday 
early morning and before the potential increases again overnight. 
Then, on Wednesday, expect the slow drag across the area and fragmentation 
of the initial band of this frontal mass. Rain and showers become 
likely overnight into the early morning and begin to wane through 
the afternoon. The NWP suite swings winds around to the southwest 
remaining 10-15 knots through Tuesday. Then on Wednesday, light to 
moderate winds keep the southerly component tending south-southwesterly 
before increasing at times. Winds increase becoming moderate to strong 
later on Wednesday from the afternoon with speeds ranging from 14-22 
knots. A Small Craft Warning becomes likely from Wednesday afternoon 
as winds flirt with the 20-knot threshold and become strong. Concerning 
seas, the UK and GFS wave models increase states towards the mid-moderate 
criteria with wave heights near 7 feet. With the approach of the 
prefrontal trough, there exists the potential for thunderstorm development 
and enhanced convection on Wednesday morning. With the upper level 
support, increase in moisture, and increasing instability, a Thunderstorm 
Advisory is becoming increasing likely, particularly during the morning. 
No other watches or warnings are anticipated. 

Long term (Thursday-Friday)
On Thursday, the prefrontal trough lingers to our east and southeast 
while the low associated with this trough brings the main frontal 
band through the area. Expect a frontal passage on Thursday morning 
before winds veer sharply to the northwest. Global models keep the 
moderate to strong southwesterly regime into the early portions of 
Thursday before the FROPA timed near 12-15Z. Anticipate a frontal 
band to cross the area lowering cloud bases and bringing showers. 
QPFs continue to diverge across the suite adding quite a bit of uncertainty 
for the expected rainfall amount. Moderate to heavy precipitation 
could stall overhead perhaps producing higher values; especially 
during the morning hours. Then, winds veer northwesterly and north 
and begin to ease gradually becoming moderate by the evening. Models 
have a relative good handle on the frontal timing. High pressure 
then moves in from the northwest into Friday settling conditions 
and clearing cloud cover. Friday then sees brighter afternoon skies 
with easing winds. The Small Craft Warning will likely end on Thursday 
afternoon after conditions have improved.