Bermuda Weather Service Forecast Discussion

For Monday, October 15, 2018  08:00 UTC

FORECASTER - Ken Smith 

Bermuda Weather Service Forecast Discussion
For AM Monday, 15 October 2018
Forecaster:  KS

NOWCAST (Today)
Satellite imagery shows a large patch of low cloud cover clearing 
to the east of the local marine area and relatively clear skies all 
quadrants.  RADAR is clear all quadrants beyond 50nm.  Our current 
sky condition is scattered and winds are light to moderate north-northeasterly. 
 The latest north Atlantic surface analysis from the Ocean Prediction 
Center shows seas in our area less than 6 feet which initializes 
well with the local wave model.

All global models are in generally good agreement throughout the 
period.  UKMO is often a few knots stronger on the wind forecast 
and the forecast is a blend of UKMO and GFS in this regard.

As yesterday’s cold front lingers near to our south and east high 
pressure is building to our north.  This high will gradually move 
eastward while extending a ridge southwest to the Carolinas.  This 
will tend to dissipate the front near to our east and south and provide 
mainly fine weather today with moderate northeasterly winds easing 
light to moderate east-northeasterly tonight.  Seas will be slight 
to moderate today and tonight.

There are no watches or warnings at this time and none are expected 
through tonight.

SHORT TERM FORECAST (Tuesday & Wednesday)
By Tuesday morning the high will be centered to our distant northeast. 
 A ridge will extend southwest across Bermuda and west to the Carolinas. 
 This will continue to provide fine to fair weather for Tuesday. 
 Light to moderate east-northeasterly winds will soon become light 
and variable Tuesday, then settle light to moderate southwesterly 
overnight as the ridge axis drifts to our south.  Meanwhile a cold 
front will move southwest out of the U.S. Tuesday and gradually advance 
towards Bermuda.  The ridge axis will gradually retreat southeastward 
allowing the front to slowly approach to our northwest.  This will 
cause the light to moderate southwesterly winds Wednesday morning 
to gradually increase to moderate by the afternoon, then moderate 
to strong overnight.  Fair to fine weather most of Wednesday will 
yield to isolated showers late Wednesday night.  Slight to moderate 
seas early Tuesday will fall smooth to slight on Tuesday, then slowly 
rise slight to moderate again on Wednesday.

No watches or warnings are expected for Tuesday.
A new Small Craft Warning is expected beginning Wednesday night.

LONG TERM FORECAST (Thursday & Friday)
The cold front will move in Thursday morning and push to our southeast 
around midday.  Expect isolated to scattered showers through the 
morning.  Stability indices also indicate a chance of morning thunder 
with the frontal passage.  As the front passes moderate to strong 
southwesterly winds will quickly veer westerly, then northwesterly 
in the afternoon.  The front will continue to move away south and 
southeast leaving mainly fair weather for Friday, though isolated 
showers are still possible.  Moderate to strong north-northwesterly 
winds Friday morning will gradually veer and ease becoming moderate 
northeasterly.  Seas will be increasing on Thursday moderate to rough, 
likely remaining moderate to rough for Friday.

A Small Craft Warning is expected throughout Thursday and likely 
Friday.
A Thunderstorm Advisory may be necessary Thursday morning.

TROPICAL INFORMATION
There are no tropical cyclones at this time.

Shower and thunderstorm activity has increased overnight in
association with a broad area of low pressure located over the
southwestern Caribbean Sea.  This system is moving slowly
west-northwestward, and some additional development is possible
before it moves inland over Central America by tonight or Tuesday.
Regardless of development, locally heavy rainfall, which could cause
flash flooding, is possible across portions of Central America for
much of the week.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...low...30 percent.

...TROPICAL WAVES...

A low amplitude tropical wave extends its axis along 44W from 
01N-12N, moving west at 15-20 kt. A 700 mb trough is shown by 
model analyses with this wave. TPW imagery indicates abundant 
moisture in its environment. Scattered moderate to strong 
convection is occurring from 06N-14N within 180 nm of the wave
axis.

A tropical wave extends its axis along 51/52W from 08N-21N, 
moving west at 10-15 kt. A 700 mb trough is depicted by model 
analyses with the wave, and there is a local maximum in TPW. A
recent ASCAT pass shows that the tropical wave is well-defined at
the surface with 25-30 kt winds from 16N-18N within 60 nm of the 

wave axis. Scattered moderate to strong convection is noted from 

15N-18N between 48W-52W. Scattered showers are noted from 19N- 
22N between 46W-50W and along the wave's axis south of 13N. It is
likely that the tropical wave along 44W will be merging with this 

wave over the next 24 hours. Expect plenty of convective activity 

near and in between both waves. Moisture associated with these 
waves is likely to enhance showers and thunderstorms over the 
Lesser Antilles Tuesday into Wednesday, and this activity will
spread to the eastern Caribbean Sea during the middle of the 
week.

A tropical wave extends its axis along 62W from 08N-21N moving
west at 10 kt. Scattered showers are noted just north of the
northern Leeward Islands and Virgin Islands. Additional scattered
showers and storms are seen from 11N-14N between 55W-60W. The 
northern end of the wave is moving into an area of diffluent flow 

aloft this morning. Enhanced showers and thunderstorms are 
possible today for the Leeward Islands, Virgin Islands, and 
Puerto Rico. This wave is expected to continue weakening into 
Tuesday as it moves toward the central Caribbean.