Bermuda Weather Service Forecast Discussion

For Friday, July 19, 2019  19:00 UTC

FORECASTER - Andrew Bufalino 

NOWCAST (Friday)
Satellite and radar imagery indicates convection developing to our 
south and west. Most of this activity has only recently developed 
over the past hour or two, potentially due to a very discrete convergent 
zone traversing into the area. Unfortunately nothing was analyzed 
on the 01-03UTC ASCAT due to the pass entirely missing ourforecast 
domain. Little precipitation is anticipated across the island this 
evening however isolated showers are to continue across the marine 
area, particularly with the passage of this discrete convergent zone. 
If a shower impacts Bermuda, they will be heavy but brief as most 
showers are only tapping into the lowest 10,000ft of steering flow. 
Deep convection in the form of cumulonimbus (Cb) was observed to 
our southeast (>30nm) earlier this afternoon however no strikes were 
observed or analyzed. Note, most Cb developed rapidly in between 
routine observations, growing from Cu to Cb with pronounce glaciation 
within the 30 minute window. Although thunderstorms are not on the 
forecast across the marine area, be wary that the current environment 
is very unstable Ė given the lack of Morganís Cloud and upper level 
support, thunderstorms have remained off the forecast.  OPC has analyzed 
Bermuda as having around 3ft seas, which agrees with the UK wave 
model output. No watches or warnings are in effect. 

AVIATION: Active RWY30 as winds remains west-southwest around 8-12 
knots. VFR conditions to remain in place, however an odd shower later 
this evening cannot be ruled out (<30% chance). For current airfield 
information please visit: http://www.weather.bm/Aviation

SHORT TERM (Saturday and Sunday)
Upper level and surface ridging will continue to reinforce itself 
across Bermuda over the course of the weekend. Surface winds will 
originate from the west-southwest, although EC is currently forecasting 
a more westerly (~270) component. Regardless of the wind regime, 
Morganís Cloud is not likely. Nearby ridging will further exacerbate 
the suppression of convection across the forecast area. Seas are 
expected to continue in the 2-4í range. No watches, warnings or advisories 
are expected during the short term forecast time frame.
  
LONG TERM (Monday and Tuesday)
The upper levels begin to shift during the long term period with 
an upper trough amplifying over eastern Canada and America, driving 
broad poleward flow and atmospheric destabilization. This evolving 
upper level pattern will help spawn a surface low near Nova Scotia 
with an associated strong cold front shifting over eastern CONUS 
and into the northwest Atlantic. As a result, the surface ridge will 
start to weaken and shift northeast, away from the forecast region. 
For Bermuda, a humid and very unstable prefrontal air mass will lock 
itself overhead, potentially causing an increase in showers. However, 
latest 12UTC EC and GFS guidance holds onto a firm ridge, marking 
a moderately-strength cap around 850hPa, likely to inhibit local 
convection. No watches, warnings or advisories are expected during 
the long term forecast time frame.  

TROPICAL WEATHER OUTLOOK

NWS National Hurricane Center Miami FL
200 PM EDT Fri Jul 19 2019 - for the North Atlantic...Caribbean 
Sea and the Gulf of Mexico:
Tropical cyclone formation is not expected during the next 5 days.