Bermuda Weather Service Forecast Discussion

For Sunday, June 25, 2017  08:00 UTC

FORECASTER - Ken Smith 

Bermuda Weather Service Forecast Discussion
For AM Sunday, 25 June 2017
Forecaster:  KS

NOWCAST (Today)
Satellite imagery shows mainly mid-level clouds streaming southwestward 
across the region with no significant convection.  The NOAA Satellite 
Estimated Rainfall product shows a line of weak showers to our northwest, 
otherwise, nothing throughout the region.  Our current sky condition 
is broken and winds are light southwesterly.  The latest north Atlantic 
surface analysis from the Ocean Prediction Center shows seas in our 
area about 3 feet which initializes well with the local wave model.

UKMO and GFS are in generally good agreement throughout the forecast 
period.  The Bermuda-Azores High maintains a ridge to our south which 
is holding a cold front off to our northwest.  This will provide 
fair weather for today and tonight along with light to moderate southwesterly 
winds and smooth to slight seas.

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

SHORT TERM FORECAST (Monday & Tuesday)
The ridge to our south will begin to retreat eastward allowing the 
front to our northwest to approach.  The southerly flow around the 
western flank of the ridge will advect warm, moist air towards Bermuda 
converging ahead of the front which will now begin to approach.  
Monday is expected to start with only partly cloudy skies, becoming 
mostly cloudy in the evening with isolated showers developing evening 
and overnight.  Light to moderate south-southwesterly winds will 
veer southerly in the afternoon.  As the front continues to slowly 
approach Bermuda increased convergence will generate more shower 
on Tuesday and stability indices indicate a chance of thunder which 
has been added to the forecast.  Winds will remain light to moderate 
southerly through Tuesday night.  Seas will remain smooth to slight 
through Tuesday night.
A Thunderstorm Advisory may be required at any time on Tuesday.

LONG TERM FORECAST (Wednesday & Thursday)
The approaching cold front will move through Bermuda on Wednesday 
with showers and a risk of thunder in the morning, turning to just 
isolated showers by evening.  Thursday is expected to dawn mostly 
cloudy, with gradually decreasing cloud cover through the day.  Light 
to moderate southerly winds early Wednesday will veer southwesterly 
by afternoon, become light and variable by evening, then northerly 
light to moderate overnight.  Winds then increase to moderate Thursday 
morning and veer northeasterly by midday.  Seas will remain smooth 
to slight throughout Wednesday and Thursday.

A Thunderstorm Advisory is expected for Wednesday morning.
No other watches or warnings are expected through Thursday.

TROPICAL INFORMATION
There are no tropical cyclones at this time.

...TROPICAL WAVES...

A tropical wave came off the coast of Africa earlier today. There
is a broad area of low pressure associated with the wave, which
axis is near 20W. This wave, not depicted in the 0000 UTC analysis
map, is in a region of favorable wind shear, is in a very moist
environment and is under a divergent flow aloft, which is
supporting heavy showers and tstms from 03N-09N E of 29W.

A tropical wave is in the central Atlc with axis extending from 

16N36W to 03N40W, moving W at 20 kt within the last 24 hours. The
wave is in a region of favorable to neutral wind shear. However, 

the CIRA LPW imagery show extensive dry air in the wave 
environment, which coincide with Meteosat enhanced imagery of 
Saharan dry air and dust. This is supporting lack of convection 
N
of 5N. Numerous heavy showers and isolated tstms associated with
the ITCZ are from 02N-05N between 38W and 47W. 

A tropical wave is E of the Lesser Antilles with axis extending 

from 17N54W to inland Guyana near 05N57W, moving W at 15-20 kt 
within the last 24 hours. The wave is in a region of favorable to 

neutral wind shear S of 10N and is in a very moist environment 
with some patches of dry air according to CIRA LPW. Scattered to
isolated showers are S of 17N between 52W and 63W.

A tropical wave is in the central Caribbean with axis extending 

from 18N71W to inland Venezuela near 08N72W, moving west at 15 
knots within the last 24 hours. The wave is in a region of 
unfavorable wind shear and a deep layer dry environment that
hinder deep convection at the time.