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Area forecast discussion 
National Weather Service Mobile Alabama
414 PM CDT Monday Apr 27 2015

..heavy rainfall and a few strong to severe storms possible across
portions of the region through Tuesday...

Short term [tonight through Tuesday afternoon]... a closed upper
low pressure area North Texas will move very slowly eastward
reaching the middle Mississippi River valley Tuesday evening. Meanwhile
another significant storm system is expected to affect the region
through Tuesday afternoon as an area of surface low pressure over
the western Gulf of Mexico moves slowly east-northeast reaching the
Mississippi Delta Region by noon Tuesday. This low will then track
across extreme southeastern Mississippi Tuesday afternoon.

Moderate southerly winds and increasing moisture will occur ahead of
the low pressure systems...with precipitable water values reaching
between 1.5 to 1.9 inches. Widespread showers and thunderstorms will
spread northeast across the forecast area...mainly from midnight
tonight through early Tuesday afternoon. These showers and
thunderstorms will bring an increased potential for heavy rainfall
across portions of southeast Mississippi and the coastal sections of
southwest Alabama and the western Florida Panhandle...which could
lead to flash flooding. Therefore...a Flash Flood Watch remains in
effect for those areas with rainfall amounts of 1.5 to 2.5 inches
likely...and locally higher amounts up to 4 inches possible.

Highest sbcapes along the coastal sections are expected to range
from 500 to 1000 j/kg on Tuesday...with 0-1km helicity values
ranging from 50 to 125 m2/s2. Some storms could become strong and
possibly severe on Tuesday across the coastal sections with the
potential of producing damaging winds...marginal hail and isolated
tornadoes.

Lows tonight will range from 57 to 64 degrees inland areas...and
from 65 to 70 degrees across the coastal sections. High temperatures
on Tuesday will only reach the low to middle 70s. /22

(tuesday night through Wednesday night)...a closed 500 mb low moves
from over Arkansas toward the southeastern United States with an
associated surface low off Mobile Bay. The 500 mb feature will open
up as a closed 500 mb low over the Great Lakes which becomes the
dominant part of the large scale 500 mb trough. A 500 mb jet streak
moving from over the Great Lakes is contributing to the life of this
larger feature and the surface low associated with it will move east
from off the Florida coast east-northeast over the northern Gulf
Coast then past the Georgia coast. The increasing pace of the surface
low means the risk for severe weather is decreasing rapidly Tuesday
night and chances of rain become minimal as well Wednesday through
Wednesday night. 77/blowing dust

Long term...(thursday through sunday)...jet streak we mentioned
will help strengthen a surface high ridging over the Southern Plains
and moving east over the Ohio Valley which will keep US under a
northerly flow through late in the week. Temperatures will be 5 to 10
degrees below seasonal. As the surface ridge moves east from over the
Mississippi Valley into the middle south then off the East Coast by
Monday a surface ridge will be left extending west over the
southeastern United States...bringing return flow from the Gulf and
allowing temperatures slightly above seasonal by late Saturday
through the rest of the weekend. 77/blowing dust

&&

Aviation...regular afternoon forecast cycle...as mentioned
before...mesoscale wake low had formed behind the northern part of
the squall line which passed earlier. Although the major convective
part of this feature passed to our south...it is bringing winds
gusting 35 to 4o knots from the southeast and will persist for the
next hour or two. We updated tafs for bfm and mob for strong gusty
winds sustained 25 knots gusting to 40 knots from the south for this
afternoon. Most of the convection remains over the Gulf. Another
round of convection is possible later this evening. 77/blowing dust

&&

Marine...an area of low pressure over the western Gulf of Mexico is
forecast to slowly move east-northeast and reach the Mississippi
Delta Region by noon Tuesday. Widespread showers and thunderstorms
will spread northeast across the northern Gulf region overnight into
Tuesday. A few strong to possibly severe thunderstorms will be
possible late tonight and Tuesday. A strong northwest flow will
develop in the wake of this system by early Wednesday and continue
through Thursday afternoon. A light northerly flow will follow on
Friday. /22

&&

Preliminary point temps/pops...
Mobile 65 74 58 69 54 / 100 70 30 20 05
Pensacola 67 74 62 70 57 / 100 80 40 30 05
Destin 67 72 65 71 59 / 100 90 20 30 20
Evergreen 62 73 59 68 52 / 80 80 60 40 10
Waynesboro 59 71 54 66 50 / 90 70 40 30 10
Camden 59 71 58 66 51 / 60 80 60 40 10
Crestview 65 74 62 72 55 / 90 90 40 40 20

&&

Mob watches/warnings/advisories...
Alabama...Flash Flood Watch through Tuesday afternoon for lower Baldwin-
lower Mobile-upper Baldwin-upper Mobile.

Florida...Flash Flood Watch through Tuesday afternoon for coastal Escambia-
coastal Okaloosa-coastal Santa Rosa-inland Escambia-inland
Okaloosa-inland Santa Rosa.

MS...Flash Flood Watch through Tuesday afternoon for George-stone.

GM...none.
&&

$$

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