591 
FXUS62 KKEY 041838
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
238 PM EDT Sat May 4 2019

.DISCUSSION...
Mean layer low level ridging persists southeast of Bermuda. This
morning's KKEY RAOB sampled a gently veering profile, with above
normal PW (>90th percentile) mingled with distinct dry layers near
900 and 700 mb. Moderate southeast breezes have persisted through
the afternoon across the island chain and the marine observation 
platforms. Low level parcels remain anticyclonic, which has 
squelched the invigoration of the maritime cumulus cloud rolls. A
few have tried to sneak through the dry air layers, lasting about
15 minutes as light rain showers. Temperatures are in the upper 
80s with dewpoints in the mid 70s. 

.FORECAST...
Southeast winds will surge again tonight into the 10 to 15 knot
range, with some locations across the Straits of Florida reaching
15 knots. The low level ridge axis will sag southward into the
Straits of Florida Sunday. By late Sunday afternoon, wind 
profiles will be favorable for a reverse cloud line. However,
dewpoint depressions near 15 degC at 700 mb will challenge any
moist convection. Very little low level gradient is expected Sunday
night through Tuesday. Profiles will once again be favorable for
afternoon cloud lines along the island chain. Monday's
early afternoon thermodynamic profile will be better than 
Sunday's, although 10 degC dewpoint depressions will make it less 
than ideal. Even drier air is expected Tuesday afternoon, so
despite the favorable profiles, we have limited rain chances to
slight (10-20%) through the period. 

A continental high will spread east from the Delmarva Tuesday 
night with subtropical aspirations. Freshening easterly breezes 
are expected by Wednesday as the high takes shape over the western
North Atlantic. Despite the energetic and moistened BL, low level
inhibition will increase. Through the long term, slight rain 
chances have been retained, in line with May's climatological PoP 
(15%). The inherited forecast is on track and needs no 
adjustments. 

&&

.MARINE...
High pressure centered southeast of Bermuda will persist tonight 
and Sunday. The low level gradient will relax Sunday night through
Monday night, before high pressure rebuilds near Bermuda Tuesday 
night through Wednesday night. Moderate easterly breezes are 
expected to return Wednesday as the low level gradient tightens.

The gridded database features isolated thunderstorms across the
distant Straits of Florida, highlighting Cuba's ability to spread
late afternoon convection northward into the Straits. Steering
flow will not be ideal for these northward moving storms to make
significant progress towards the island chain. 

&&

.AVIATION...
VFR conditions are expected to prevail at the EYW and MTH island 
terminals through the rest of this afternoon and tonight. 
Southeast surface winds around 10 knots will back slightly this 
evening, then veer toward the south late tonight, becoming SSW 
around 5 knots by midday Sunday.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  80  87  80  86 / 20 10 10 20 
Marathon  81  92  81  92 / 20 10 10 20 

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...None.
&&

$$

Public/Marine/Fire...CLR
Aviation/Nowcasts....Jacobson
Data Collection......BT

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