Bermuda Weather Service Forecast Discussion

For Friday, June 22, 2018  09:00 UTC

FORECASTER - Eric Drewitz 

NOWCAST (Friday):
Current satellite shows a stationary frontal boundary extending 
SW’ward from the Canadian Maritime to Cape Hatteras with broad high 
pressure ridging extending SW’ward from the Azores to the Greater 
Antilles and encompassing Bermuda. Current water vapor imagery continues 
to show an area of cyclonic rotation that is currently centered near 
26N/66W. The majority of the convection associated with this upper-level 
low is apparent on the NE’rn edges of this low. Latest UKMET, GFS 
and ECMWF guidance is consistent with the upper-level low slowly 
drifting WSW’ward towards the Bahamas today keeping the shower and 
thunderstorm activity well to the south of Bermuda. Current radar 
imagery shows a few showers well to the southeast of the island with 
the majority of the shower activity well to the northwest due to 
the aforementioned stationary frontal boundary. The water vapor imagery 
also shows dry mid to upper-levels over Bermuda which will help inhibit 
shower potential for the morning and afternoon today. High clouds 
are expected to increase late this evening as the upper-levels moisten. 
GFS and UK guidance support the moistening of the upper-levels due 
to the persistent SW’ly synoptic flow advecting Gulf Stream moisture 
into the region. 

VFR conditions are to be expected for the morning and afternoon 
as shower activity will be minimal due to dry mid and upper-levels. 
Expect 210deg winds at 12-18kts due to the aforementioned orientation 
of the Azores-Bermuda ridge of high pressure. High clouds will begin 
to increase during the late evening hours as the upper-levels are 
expected to moisten. For current airfield information please visit:

SHORT TERM FORECAST (Saturday-Sunday):
A second upper-level low is expected to move WSW’ward towards the 
Bahamas on Saturday. The aforementioned broad high pressure ridging 
to the east will advect moisture associated with this trough into 
the region due to mid and upper-level SW’ly steering flow. 00z UK 
and 00z GFS runs are consistent with ample low level moisture advection 
due to the SW’ly winds advecting 70+ Fahrenheit dewpoints into the 
greater Bermuda area on Saturday. Conditions will improve into Sunday 
as the broad high pressure ridging that extends from the Azores to 
the Greater Antilles will build W’ward and encompass Bermuda. 00z 
GFS and UK runs are consistent in 250mb confluence which will support 
synoptic scale descent and help inhibit the chance for showers.  

LONG TERM FORECAST: (Monday-Tuesday):
Chances for showers will increase on Monday as the Azores-Bermuda 
broad high pressure ridging begins to retreat E’ward and a cold front 
to our northwest will then begin to slowly drift SE’ward to over 
Bermuda. Chances for showers and isolated thunderstorms will be greater 
on Tuesday as Bermuda will be located in an area of upper-level diffluence 
due to being located in the right-entrance region of a 250mb jet-streak 
which will provide synoptic scale ascent with ample low-level moisture. 
00z UK and GFS runs are consistent in the cold front passing over 
Bermuda later on Tuesday as the 850mb temperatures will drop between 
1-2 degrees Celsius combined with the SW’ly winds shifting to NW’ly 
by Tuesday night. 

NWS National Hurricane Center Miami FL
200 AM EDT Fri Jun 22 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