Area forecast discussion
National Weather Service Mobile Alabama
442 am CDT Friday may 24 2013
Short term...(today through sunday)...for today through tonight...
northwest flow aloft will prevail over the region today between an
amplifying upper level ridge over the plains states and a broad upper
level trough moving toward the East Coast. A much drier airmass in
the deep layers will spread southward to the Alabama/Florida coastline by late
this afternoon...so no rain is expected across our region. A surface
ridge of high pressure will build southward to the Gulf Coast behind
a passing weak cold front today...which will promote a northerly
surface flow across the forecast area. Afternoon temperatures should
be a few degrees cooler across most locations. Highs look to mostly
range in the middle to upper 80s. Mostly clear skies will continue
tonight. Drier air will advect southwestward through the forecast
area late this afternoon through tonight...with dewpoints falling
into the middle 40s to lower 50s by early Saturday morning. We expect
overnight lows to range about 5 to 10 degrees below
normal...generally from around 50 across interior/northern areas to
the middle 50s to around 60 near the coast. /21
This afternoon's wet microburst risk is low.
By Saturday morning...the upper ridge over the plains today has
shifted east...with the ridge-line just west of the miss River
Valley. A shortwave has moved over Texas by Saturday morning. Surface
high pressure was centered over the Ohio River valley...with a ridge
stretching south across the eastern Continental U.S.. for the forecast area...significantly
drier air has move over the area under northeasterly flow.
Saturday through Sunday...the shortwave over the plains moves through
the upper ridge-line...as the ridge moves east. This eastward
movement is due to a bunch of shortwave energy dancing around each
other over the northwestern Continental U.S.. the surface ridge gets a shove
east...especially over the southeastern Continental U.S. Due to the plains
shortwave.This brings back southeasterly flow to the Continental U.S....albeit a
bit on the synoptic weak side. Low level flow is stronger over the
plains...with a surface low developing over the over the Central
Plains helping to tighten the pressure gradient over the plains.
For the forecast...guidance is in pretty good agreement...so haven't
deviated. Temperatures around seasonal...with a lack of precipitation.
Long term...(sunday night on)...Sunday night through Monday...the
upper energy dancing around over the northwestern plains breaks
down...with pieces moving over the upper ridge over the plains. This
helps to Delaware-amplify the upper ridge somewhat over the
plains(especially in the gfs). The onshore flow east of the lower
miss River Valley remains onshore...but still synoptically weak as a
surface ridge has become organized over the southeastern Continental U.S.. temperatures
around seasonal continue...with precipitation again lacking.
Monday night through Tuesday...some of the upper energy digs south over
the western Continental U.S.....Forming an upper trough over the western Continental U.S..
this helps to build the upper ridge over the eastern Continental U.S.. a piece
of energy moves over the ridge to the southeastern Continental U.S....forming
either a weak upper low over the eastern gulf(gfs) or upper trough
centered over the southeastern Continental U.S./NE-ern Gulf of mex(ecmwf). The
onshore flow remains strong over the plains...weakening as one moves
east along the northern Gulf Coast. Little change in the synoptic
pattern...though moisture levels are on the increase. With the upper
low/trough east of the forecast area...and a building ridge...temperatures climb a bit
above seasonal...with rain not expected.
Tuesday night through Wednesday...the southern end of the western
trough starts to swing east...pushing the eastern upper ridge
east...and the shortwave over the southeast-eastern Continental U.S. Over the open Gulf of
mex in all the guidance. Moisture levels continue to rise...with a
chance of rain making it back into the forecast.
Wednesday night through Friday...the eastern upper ridge and the
energy moving over the plains from the western Continental U.S. Play a game of
push and shove. The ridge gets pushed to over the East Coast by
Friday evening. The surface ridge over the southeastern Continental U.S. Gets
a bit of a shove north...resulting in a more easterly synoptic flow.
Probability of precipitation have returned...but remain below seasonal. Temperatures a bit above
seasonal continue.
&&
Aviation...[12z terminal forecast discussion]...VFR conditions will
continue through the taf period. Northerly winds will increase to
around 10 knots...with a few higher gusts possible after 24/15z. /21
&&
Marine...a weak cold front will push southward into the northern
Gulf of Mexico later today into tonight. Offshore flow will increase
over the marine area through tonight as surface high pressure builds
southward into the Gulf in the wake of the frontal passage. Wind
speeds will likely reach exercise caution levels late tonight
through early Saturday morning. Surface high pressure then builds
into the southeastern U.S. This weekend...then into the northern
Gulf during the early to middle part of next week. A light to
moderate east to southeast flow should prevail through the extended
forecast period with this pattern. /21
&&
Fire weather...a front will mover south over the area today...
bringing somewhat cooler...definitely drier air. The northerly air
breaks down through the weekend...becoming southeasterly by the
beginning of the week. Generally southeasterly flow in the mixing
layer will increase moisture levels through the week.
&&
Preliminary point temps/pops...
Mobile 87 56 85 60 86 / 05 00 00 00 05
Pensacola 89 61 85 64 85 / 05 00 00 00 05
Destin 85 63 83 66 83 / 00 00 00 00 05
Evergreen 85 50 86 52 88 / 00 00 00 00 05
Waynesboro 84 51 86 54 88 / 00 00 00 00 10
Camden 83 49 87 53 88 / 00 00 00 00 10
Crestview 90 50 87 53 88 / 00 00 00 00 05
&&
Mob watches/warnings/advisories...
Alabama...none.
Florida...none.
MS...none.
GM...none.
&&
$$
21/16
