Bermuda Weather Service Forecast Discussion

For Wednesday, August 23, 2017  06:00 UTC

FORECASTER - Gary Hall 

NOWCAST (Today-Tonight):
A 1017mb high is situated to the west while ridging extends from 
the high to the northeast protecting Bermuda through this period. 
An upper level low seen to the southeast supports an inverted surface 
trough also to the southeast, but with the high firmly in place this 
will not be a factor until later in the week. Satellite imagery shows 
virtually cloud free skies and the 00Z Skew-T confirms the stable 
atmosphere in our area. Model data is consistent with keeping this 
trend through today along with generally light easterly winds and 
slight seas. No watches, warnings or advisories are in effect.

AVIATION: VFR no hazards. TXKF runway winds generally easterly and 
< 10 knots.

SHORT TERM FORECAST (Thursday-Friday):
Thursday promises to be another fine day as the surface troughing 
remains to the southeast (albeit not that far) and the frontal boundary 
to the northwest is still a day or more away from affecting the island. 
Winds will veer southerly through Thursday, though become light, 
and at times light and variable before intensifying southwesterly 
light to moderate on Friday as the front draws nearer and the narrow 
ridge erodes. The models are in good agreement with this solution, 
including the overall timing. All indications are for an increase 
in moisture through the day on Friday with possible showers to develop 
as early as Friday afternoon, but more likely from the evening/night 
onward. Seas continue to be in the 1-3 foot range and no watches, 
warnings or advisories are expected.

LONG TERM FORECAST (Saturday-Sunday):
The front will be draped to our near north through the weekend and 
is well supported by a deep upper level trough extending southward 
from the Labrador Sea. This seems a bit uncharacteristic for August, 
but given the available moisture and the dynamic feature as it is, 
showers and thunderstorms seem quite probable on both days. The models 
do not bring the front through so expect southwesterly moderate winds 
as a rule as Bermuda lies on the southern periphery of the boundary. 
Model consistency remains good and confidence continues to be fairly 
high. A thunderstorm advisory is highly probable for this period, 
though as of right now the winds are not expected to reach small 
craft warning criteria. 

TROPICAL OUTLOOK:
NWS National Hurricane Center Miami FL
200 AM EDT Wed Aug 23 2017
For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. A broad area of low pressure associated with the remnants of 
Harvey is located over the eastern Bay of Campeche. Although thunderstorm 
activity has increased over the northern portion of the system tonight, 
recent satellite wind data indicate that low pressure area lacks 
a well-defined circulation at this time.  Environmental conditions 
are conducive for development, and a tropical depression or tropical 
storm is very likely to form today or tonight while the low moves 
northwestward at about 10 mph across the western Gulf of Mexico, 
possibly reaching the northwestern Gulf coast late Friday.

Regardless of development, this system is likely to slow down once 
it reaches the coast, increasing the threat of a prolonged period 
of heavy rainfall and flooding across portions of Texas, southwestern 
Louisiana, and northeastern Mexico into early next week.  This
system could also produce storm surge and tropical storm or hurricane 
force winds along portions of the Texas coast later this week, and 
Tropical Storm or Hurricane Watches could be required later today 
for portions of the coast of northeastern Mexico, Texas,
and southwestern Louisiana.  Interests in these areas should monitor 
the progress of this system, and refer to products issued by your 
local National Weather Service office for more information.  An Air 
Force Reserve reconnaissance aircraft is schedule to investigate 
the low this morning.

* Formation chance through 48 hours...high...90 percent.
* Formation chance through 5 days...high...near 100 percent.

2. An area of disorganized showers and thunderstorms stretching 
across the Bahamas, southern Florida, and the adjacent waters is 
associated with a trough of low pressure.  Any development of this 
system during the next few days should be slow to occur while it 
drifts northward over Florida and the adjacent waters. Environmental 
conditions could become a little more conducive for tropical or subtropical 
development over the weekend when the system begins to move northeastward 
over the western Atlantic.  Regardless of
development, very heavy rain and flooding is possible over portions 
of the Florida peninsula during the next few days.  Please refer 
to products from your local National Weather Service office for more 
information on this system.

* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...low...30 percent.
Forecaster Brown