Bermuda Weather Service Forecast Discussion

For Friday, January 18, 2019  20:00 UTC

FORECASTER - Ken Smith 

Bermuda Weather Service Forecast Discussion
For PM Friday, 18 January 2019
Forecaster:  KS

NOWCAST (Tonight)
Satellite imagery shows a relatively weak cold front approaching 
to our northwest.  There are scattered spherics returns along the 
front but all are well north of our latitude.  RADAR shows a well-defined 
line of light to moderate showers now about 75nm to our northwest. 
 Our current sky condition is broken and winds are moderate southwesterly. 
 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 with the exception 
that GFS is somewhat move aggressive with the cold front moving in 
Monday morning both with timing, wind strength and precipitation 
totals.  The current forecast leans towards the UKMO solution.

A low pressure system to our northwest will pass to our north driving 
a weak cold front through Bermuda late tonight and early Saturday. 
 Fair weather this evening will become showery as the front passes 
later this evening and tonight.  Moderate south-southwesterly winds 
may increase moderate to strong for a time tonight, veering moderate 
northwesterly near dawn.  Seas will remain slight to moderate through 
tonight.

A Small Craft Warning has been issued for tonight.

SHORT TERM FORECAST (Saturday & Sunday)
A few early morning showers on Saturday are likely as the cold front 
departs to our southeast.  High pressure to our west will bring improving 
conditions for the remainder of Saturday.  Fair conditions are expected 
through sunset on Sunday as well as the high departs.  A deep low 
pressure moving northeast into the Canadian Maritimes later Sunday 
will drive a strong cold front to Bermuda bringing widespread rain 
and showers as well as a threat of thunder Sunday night.  Light to 
moderate northwesterly winds Saturday morning will ease to light 
in the afternoon, then become light and variable Saturday evening. 
 Winds then settle southeasterly Saturday night and increase to moderate. 
 Winds increase on Sunday as the front approaches, becoming strong 
southerly by Sunday afternoon and strong to gale force with gale 
force gusts by late Sunday evening through Sunday night.  Gusts to 
storm force cannot be ruled out at this time.  Slight to moderate 
seas Saturday morning will fall smooth to slight during the morning, 
then gradually build moderate to very rough on Sunday in response 
to the increasing winds.  

No watches or warnings are expected for Saturday.
A new Small Craft Warning is expected by Sunday afternoon through 
evening, transitioning into a Gale Warning Sunday evening through 
Sunday night.
A Thunderstorm Advisory may be required Sunday night, potentially 
a Severe Weather Watch/Warning.

LONG TERM FORECAST (Monday & Tuesday)
Monday morning is expected to dawn with the cold front over Bermuda 
producing widespread rain and showers and strong to gale force south-southwesterly 
winds.  A chance of thunder remains but will be decreasing.  As the 
front clears to our southeast on Sunday winds veer westerly and ease 
strong to near gale westerly into the afternoon, then veer west-northwesterly 
overnight and may increase strong to gale force again for a time 
as colder unstable air pushes southward over Bermuda.  Tuesday is 
expected to be mainly fair but cold due to strong cold advection 
on the eastern flank of the high behind the departing cold front. 
 Strong to near gale northwesterly winds Tuesday morning will ease 
moderate to strong in the evening, then veer northerly and ease slightly 
overnight.  Seas are expected to remain moderate to very rough across 
the region throughout Monday and Tuesday.

A Gale Warning is expected to still be in force Monday morning, 
ending by afternoon, though a new Gale Warning may be issued for 
Monday night as conditions warrant.  
A Small Craft Warning will be needed between Gale Warnings on Monday 
and throughout Tuesday.