Bermuda Weather Service Forecast Discussion

For Wednesday, September 20, 2017  19:00 UTC

FORECASTER - Ken Smith 

Bermuda Weather Service Forecast Discussion
For PM Wednesday, 20 September 2017
Forecaster:  KS

NOWCAST (Tonight)
Satellite and RADAR imagery both show that the plume of tropical 
moisture than has been running northeast over Bermuda with showers 
and thunderstorms has now drifted off to the east and apart from 
isolated light showers west and northwest, mainly fair conditions 
prevail.  Our current sky condition is scattered and winds are moderate 
occasionally light southwesterly.  The latest north Atlantic surface 
analysis from the Ocean Prediction Center shows seas in our area 
about 9 feet which initializes well with the local wave model.

UKMO and GFS are in generally good agreement throughout the forecast 
period.  Tropical Storm Jose is expected to gradually weaken as it 
meanders to our distant north-northwest.  Jose is not a threat to 
Bermuda at this time, however, as it turns south, then west again 
it may close to within 400nm and become a potential threat once again 
for a short time, though the primary influence of Jose on Bermuda 
will be moderate to rough swells.  Meanwhile, hurricane Maria will 
depart Puerto Rico this evening headed north of Hispaniola, then 
gradually turn northwest and north over the next couple of days following 
a very similar path to Jose.

Tonightís forecast is for mainly fair conditions, though isolated 
showers cannot be ruled out as the plume of tropical moisture lingers 
near to our west and southwest.  Moderate southwesterly winds will 
ease light to moderate overnight, and seas will remain moderate to 
rough with northwesterly swells from Jose.  Stability indices no 
longer indicate a threat of thunder, and the spherics returns which 
lingered just outside the northeastern marine area today have also 
either died out or moved away northeast, hence the Thunderstorm Advisory 
has ended.

A Small Craft Warning remains in effect through tonight.

SHORT TERM FORECAST (Thursday & Friday)
Tropical Storm Jose will continue to meander around to our distant 
north-northwest, first turning south, then west while slowly weakening 
over the next couple of days.  At the same time hurricane Maria will 
slowly begin to march north-westwards, passing east of Turks and 
Caicos Islands on Friday.  The plume of tropical moisture will linger 
near to our east and southeast.  The forecast for Thursday and Friday 
is for mainly fair conditions, though isolated, mainly light showers 
are possible both days.  Light to moderate southwesterly winds will 
back south-southwesterly later Thursday, southerly by Friday afternoon, 
then southeasterly Friday night.  Seas will remain moderate to rough 
with northwesterly swells on Thursday.  Swells shift north-northwesterly 
and begin to diminish Friday night.

A Small Craft Warning has been issued valid through Thursday.  This 
will likely be extended through Friday.

LONG TERM FORECAST (Saturday & Sunday)
Tropical Storm Jose will continue to meander to our distant northwest 
while gradually weakening.  Hurricane Maria will turn northward and 
pass roughly midway between Bermuda and the U.S. east coast, coming 
abeam of Bermuda Sunday night.  At this point it looks as though 
Maria will remain just outside the 400nm range criteria and therefore 
will likely still not be considered a threat at this time, however, 
it would only take a small eastward drift in the track to make this 
system a potential threat to Bermuda.  Never-the-less, as Joseís 
influence gradually wanes, Maria will begin to makeís itís approach 
known.  Mainly fair conditions are expected to persist with just 
isolated light showers both Saturday and Sunday, but expect increased 
cloud cover Saturday night through Sunday.  Also, moderate to rough 
north-northwesterly swells will likely fall to moderate and become 
confused on Saturday, then shift south-southwesterly later Saturday 
in advance of Maria and begin to build moderate to rough on Sunday. 
 Light to moderate southeasterly winds Saturday will gradually increase 
to moderate Saturday through Sunday.

A Small Craft Warning will likely be required throughout Saturday 
and Sunday for rough seas, though conditions may briefly fall below 
warning criteria for a time Saturday.

TROPICAL INFORMATION
NHC continues to produce forecast advisories on tropical storm Jose 
and hurricane Maria.  Neither system is a threat to Bermuda at this 
time.  Also, former tropical storm Lee, currently a remnant low, 
may reintensify at any time.

...SPECIAL FEATURES...

At 20/1800 UTC, major Hurricane Maria is located near 18.4N 66.9W
or about 13 nm W of Arecibo, Puerto Rico. The present movement of
Maria is northwest at 10 kt. The estimated minimum central 
pressure is 961 mb. Maximum sustained winds are 100 kt with gusts
to 120 kt, Category 3. Numerous strong convection is within 120 

nm of the center. Scattered moderate to isolated strong convection
is elsewhere within 210 nm of the center. Maria is moving across 

Puerto Rico today, and will pass just north of the northeast coast
of the Dominican Republic tonight and Thursday. Please see the 
latest NHC Forecast/Advisory under AWIPS/WMO headers 
MIATCMAT5/WTNT35 KNHC for more details.

At 20/1800 UTC, Tropical Storm Jose is located about 121 nm SSE 

of Nantucket Massachusetts near 39.2N 69.3W, moving northeast at 
7
kt. The estimated minimum central pressure is 976 mb. Maximum 
sustained winds are 60 kt with gusts to 75 kt. Scattered moderate 

convection lays on the NW quadrant of the storm from 38N-42N 
between 70W-73W. Jose is a large system. Tropical-storm-force 
winds extend outward up to 178 nm from the center. Please see the 

latest NHC Forecast/Advisory under AWIPS/WMO headers 
MIATCMAT2/WTNT22 KNHC for more details.

...GALE WARNING...

A 1007 mb low in the central Atlc, the remnants of former 
tropical cyclone Lee, is located near 18N46W. Scattered moderate 

convection is over the NE quadrant from 17N-25N between 42W-45W 

Gale-force winds ore over the NE quadrant of the low...within 270
nm of the center. An increase in the organization of the deep 
convection would result in the regeneration of Lee as it moves 
northward over the central Atlantic Ocean. There is a medium 
chance for tropical cyclone re-development within the next 48 
hours.

...TROPICAL WAVES...

A tropical wave is in the E Atlantic with axis extending from 
21N34W to 06N33W, moving west at 20 kt. The wave is in a region 
of 
moderate low to middle level moisture N of 13N, and abundant
moisture S of 13N, as shown by SSMI TPW imagery. A well defined
surface reflection is also noted. Widely scattered moderate
convection is from 05N-13N between 28W-40W. 

A tropical wave is in the W Caribbean with axis extending from 
20N85W to 07N88W, moving west at 20 kt. SSMI TPW imagery 
indicates the presence of some dry air intrusion in the wave 
environment. That along with strong subsidence aloft, and strong 

vertical wind shear, produces a lack of convection over the NW 
Caribbean.