Bermuda Weather Service Forecast Discussion

For Monday, October 19, 2020  20:00 UTC

FORECASTER - Troy Anderson 

Nowcast (Monday)

During the daytime, the island experienced a true mix of sun and 
clouds in which much of the cloudier morning periods yielded to provide 
a much more bright and sunny afternoon. A few passing early morning 
showers dampened the island during the morning but decreased allowing 
a mostly dry afternoon. Northeasterly winds, occasionally out of 
the east-northeast, remained quite breezy, maintaining moderate to 
strong with higher gusts in and around the morning showers. Gusts 
near 33 knots were recorded on local AWOS sensor Crescent and this 
windy regime remained through most of the day. 

The latest GOES 16 Visible satellite imagery continues to show the 
steady flow of maritime stratocumulus from the northeast which have 
since thinned out from this morning and upper level cirrus creeping 
in from the southwest in association with a distant trough. While 
RADAR imagery is currently out of service, the NOAA estimated rainfall 
product indicated precipitation to the distant southwest and southeast 
associated with recently designated TS Epsilon. Concerning Epsilon, 
the system has spent most of the day battling wind shear and dry 
air and continues to have the comma shape indicative of the penetrating 
elements aforementioned. The latest global model consensus brings 
an intensifying system to our east, likely to near or be at hurricane 
strength at its closest point of approach however, how far or close 
east is still very uncertain. The trend appears to resemble a side-swipe 
from the east but nonetheless, it is expected to bring tropical storm 
to hurricane conditions and seas nearby. Epsilon is currently a potential 
threat to Bermuda and preparations should be as soon as possible. 
This morning’s sounding highlighted the drying out trend under an 
inversion near 8,000 ft and this allowed light and a few moderate 
showers to develop.

In analysis of the upper levels, Bermuda planted under the influence 
of ridging with troughing to the east and the distant west. Near 
the surface, a rather strong high pressure cell (Near 1036 hPa) continues 
to extend ridging from the north, although a few troughs remain within 
the overarching flow. As TS Epsilon and a distant low pressure to 
the northeast continue to nudge up against the high pressure area, 
expect the pressure squeeze to maintain the windy nature while the 
constant flow of maritime stratocumulus clouds from the northeast 
will be warmed from below and allow a few showers to develop in the 
area. Anticipate mainly light overnight showers with the slight chance 
of a moderate shower. In between bouts of showers and cloud cover, 
expect dry but gusty periods. The UK and GFS initialize well and 
continue the gusty wind regime with high-end moderate to strong near 
east-northeasterly winds and higher gusts in and around showers.

GFS MOS continues to trend temperatures towards a low near 76F and 
with the unchanged air mass, temperatures are expected to trend near 
MOS guidance +/- 1 degree. The latest OPC Wave Analysis holds near 
9-12-foot seas in our area during the nowcast and this verifies well 
with UK wave and local models thus the Small Craft Warning has been 
maintained. Confidence is moderate through the nowcast and no other 
watches and warnings are expected.

Aviation: Mainly VFR conditions are expected as wind from TXKF will 
be 16 knots from 070 degrees while the chance for overnight showers 
and gusts exists.  For more information please see www.weather.bm/aviation 


Short Term (Tuesday-Wednesday)

In the upper level analysis, anticyclonic flow overhead and to the 
west remains for a time while a low forms to the southeast, vertically 
stacking TS Epsilon. Expect an upper trough to develop over the area. 


Near the surface, expect the pressure squeeze responsible for the 
maintenance of the winds to remain carrying showers within the flow. 
Much of Tuesday morning is expected to be in and out of showers with 
a decrease towards the afternoon. The NWP suite continues to bring 
in moisture in the northeasterly flow as Epsilon is expected to creep 
northwestward. At this time, conditions are expected to become more 
conducive for development over warm surrounding waters and the decrease 
to low wind shear. This may provide Epsilon a strengthening window 
prior to its CPA (Friday near 9 am at the moment). Expect gusty conditions 
to persist prior to the approach of an overnight band during the 
end of the short term period associated with Epsilon. Slight disagreement 
exists with the timing of the onset of the potential feeder band 
but the trend remains overnight Wednesday towards early Thursday. 
Seas are expected to continue to build rather quickly becoming hazardous 
by Wednesday. Both the local wave model and UK wave models increase 
rough seas towards 20 feet by the end of the period. Concerning watches 
and warnings, a tropical storm watch is likely to be implemented 
early Tuesday and a hurricane watch may hang in the balance. 

Long Term Period  (Thursday- Friday) 

Expect the gradual approach of intensifying Epsilon to from the 
southeast bringing hazardous and dangerous seas and swells, tropical 
storm to storm force winds with hurricane force gusts, and very heavy 
rain and showers. A tropical storm warning is likely to be in effect 
while a hurricane watch/warning may be implemented for the dangerous 
surf and swells. Models continue to hint at the potential passage 
of a feeder band near early Thursday. The onset of tropical storm 
force winds is also anticipated to begin on Thursday.

Timing is handled pretty well by the NWP suite that far out but 
as expected towards the end of the forecast period the overall expectation 
is for the degradation of conditions from Thursday through Friday. 
A Tropical Storm Warning is likely to be in effect and a hurricane 
watch is still on the table. The latest track consensus favored a 
slight jog to the east but as the storm is currently near a stationary 
movement, any expected motion features high levels of uncertainty. 
Nonetheless, the latest official track brings a high end category 
1 hurricane to our east with a CPA near Friday midday.

Tropical Discussion and Outlook

NWS National Hurricane Center Miami FL       AL272020

500 PM AST Mon Oct 19 2020

...EPSILON REMAINS STATIONARY OVER THE CENTRAL ATLANTIC...

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At 500 PM AST (2100 UTC), the center of Tropical Storm Epsilon was

located near latitude 25.5 North, longitude 55.5 West.  Epsilon 
is

nearly stationary. A slow northward motion is expected tonight, 


followed by a northwestward or west-northwestward motion with an 


increase in forward speed through midweek.  On the forecast track, 


Epsilon is forecast to approach Bermuda on Thursday. 

Maximum sustained winds are near 45 mph (75 km/h) with higher gusts.

Gradual strengthening is expected during the next couple of days, 


and Epsilon is forecast to be at or near hurricane strength on

Wednesday.

Tropical-storm-force winds extend outward up to 275 miles (445 km), 


primarily to the north of the center.

The estimated minimum central pressure is 998 mb (29.47 inches).


HAZARDS AFFECTING LAND

----------------------

SURF: Swells generated by Epsilon are expected to affect Bermuda 


for the next several days.  These swells are likely to cause 

life-threatening surf and rip current conditions.  Please consult 


products from your local weather office.

NEXT ADVISORY

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Next complete advisory at 1100 PM AST.

$$