Bermuda Weather Service Forecast Discussion

For Saturday, June 23, 2018  09:00 UTC

FORECASTER - Jenna Macgregor 

NOWCAST (Today)
Current RADAR shows isolated showers moving northwards towards our 
area which was indicated by the 00Z Skew-T which showed some instability 
in the lower levels. Closer analysis shows slight troughing in the 
isobars which was well supported in a number of runs of both the 
UK and GFS models. However, as the 300 hpa charts show high pressure 
aloft, I expect any showers to be light. The models show this trough 
weakening around noon as the Bermuda-Azores high takes charge once 
more and by mid-afternoon I expect any remnants of the trough to 
have cleared our area.  This will leave fine conditions with some 
sunny spells for the rest of today which will continue through tonight 
High dew points, currently around 75F/24C so it will feel humid although 
light to moderate winds will provide some relief. No watches/ warnings/ 
advisories expected.

AVIATION: 30% risk of MVFR conditions until 1200Z due to cloud bases 
SCT/BKN 1200  1400FT. Otherwise VFR. Winds, 200 10-15 KT with crosswind 
component close to full wind strength. 

SHORT TERM FORECAST (Sunday-Monday)

Models show strong agreement in an upper and surface high across 
Bermuda on Sunday. This will leave us with plenty of sunshine through 
the day and largely clear skies overnight. However, overnight into 
Monday a weak upper trough does move across our area and models hint 
at some moister air moving across which  may allow isolated showers 
to form during the pre-dawn period. During the rest of Monday, largely 
fine but it is likely to turn increasingly cloudy through the afternoon 
and evening as a front approaches from the northwest. Models suggest 
some convergence lines running ahead of this front which may be enough 
to trigger a shower or two. No watches/warnings/advisories expected. 



LONG TERM FORECAST (Tuesday- Wednesday)

On Tuesday, we see a change to more unsettled conditions as a showery 
front moves across our area. GFS and UKMO models suggest there may 
be isolated showers in the morning with more organised activity arriving 
during Tuesday afternoon and continuing into the overnight period. 
Stability indices from both of these models show there is a slight 
chance of thunderstorms with this frontal system and potential airfield 
and thunderstorm warnings and marine advisories are under review. 
Winds are expected to strengthen during Tuesday morning as this system 
approaches with winds speeds reaching around 20 knots during the 
afternoon. By this time, winds should have veered to westerly so 
crosswind component is slightly less than full wind strength. Small 
Craft Warning is likely to be issued nearer the time. Current model 
runs keep the frontal system to our south on Wednesday as high pressure 
builds behind.  Vertical profiles suggest we could see a few showers 
as moisture is confined to the lower levels of the atmosphere but 
with moderate to strong winds, we are likely to get some mixing which 
should allow some sunny spells as well.


TROPICAL UPDATE 

NWS National Hurricane Center Miami FL
200 AM EDT Sat Jun 23 2018

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Tropical cyclone formation is not expected during the next 5 days.
Forecaster Avila