Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 271741 AAA

Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
1241 PM CDT Thu Oct 27 2016

.DISCUSSION...See updated information below.


.UPDATE...No significant changes to the forecast are necessary. A
shortwave trough will continue to move across northern AL this
afternoon, but moisture will be very limited across our area ahead
of this feature. A few isolated/brief showers will be possible over
interior N/NW portions of the area and also near the coast, but the
probability of measurable rain mostly remains less than 20 percent.
High temperatures this afternoon still look on track to reach the
lower to mid 80s. /21


18Z issuance...VFR conditions will prevail through the afternoon with
scattered to locally broken cumulus decks with bases of 3-5 KFT AGL
along with broken mid to high cloud cover. An isolated SHRA will be
possible, but coverage should be few and far between and left mention
out of the local TAFs. Patchy MVFR fog will be possible over a few
locations early Friday morning. Confidence was high enough to mention
MVFR visibility in the KMOB TAF primarily between 28.09-14Z. /21


PREV DISCUSSION... /issued 422 AM CDT Thu Oct 27 2016/

NEAR TERM /Now Through Thursday night/...Mid level short trof just
west of the lower MS river valley early this morning will dampen
further east across the north central gulf states today then shift
east of the forecast area by 12z fri. Ahead of this system a few
isolated showers were noted over central parts of MS tracking
eastward quickly most likely passing north of the forecast area
later this morning and this afternoon. Other showers were located
offshore mostly south of the MS coast tracking westward. Latest model
soundings continue to show very limited moisture across the forecast
area today and tonight leading to isolated coverage across western
and coastal areas of the forecast area through this afternoon. Latest
hi res data both the HRRR and RUC13 continue to support this
reasoning depicting very limited coverage also occurring mostly
offshore and to the west. As a result will stay close to the current
forecast for inland areas today decreasing the coverage to slight
chance or isolated offshore also. Latest model soundings also depict
limited instability suggesting any measurable rain that does occur
will continue to be in the form of light showers. With a light
onshore flow during the afternoon and evening hours yesterday some
low level moisture has advected inland ahead of this system leading
to some patchy fog near the sfc. With sfc dewpts in the lower to
middle 60s generally along and south of the I-10 corridor believe the
best coverage of fog will be over inland areas generally over the
lower half of the forecast area early this morning. For late tonight
and early fri morning with less mixing in the boundary layer thus
leading to better decoupling near the sfc believe we will see better
coverage of fog...mainly radiational...occurring over most inland
areas beginning around midnight tonight continuing through about 14z
or 8am fri morning. With light winds near the sfc fog could become
dense at times occurring mostly an hour or two before sunrise. Will
continue to monitor this fog situation closely and issue any
advisories if needed. Day and night temps will continue to be above
seasonal averages climbing to the middle 80s inland...lower 80s near
the coast followed by lows in the middle 50s well inland and the
upper 50s to lower 60s closer to the coast. 32/ee

SHORT TERM /Friday Through Saturday night/...Upper energy moving
east over the US/Canadian border will flatten an upper ridge
stretching north over the US plains into the weekend. By Saturday
evening, it stretches east over the northern Gulf coast from
Southern Plains, but then begins to rebuild into Sunday over the
Plains as upper energy digs south over the West Coast and the
Northeast. Surface high pressure centered over the Tennessee/Ohio
River Valleys gets pushed south, becoming centered over the
Southeast. With subsidence from the upper ridge maintaining control
over the FA and surrounding areas, temperatures remain above seasonal
levels. Highs in the mid to upper 80s, closer to 80 along the coast,
expected. Lows in the mid to upper 50s, low 60s along the coast. dry
northeast to east flow will help to create a dry forecast, with no
rain expected.


LONG TERM /Sunday Through Wednesday/...An upper ridge rebuilds over
the Plains, then swings east as the western Conus system swings east
and another digs south over the East coast. Ultimately, the upper
ridge moves east of the Mississippi River by Wednesday, then stalls.
With continued subsidence from the ridge over the FA through the
extended, temperatures well above seasonal continue. Also, the
surface ridge over the Southeast shifts north, to over the
Appalachians through the extended, restoring onshore flow by mid
week. Up to this point, moisture levels are not expected to rise high
enough for showers to return to the forecast, so a dry forecast is
expected to continue.


MARINE...A weak mid to upper level disturbance tracking eastward
across the region today and tonight will help lead to more isolated
showers across the marine area mainly today. Weak high pressure near
the surface will persist through early fri then strengthen from the
north and northeast as a surface ridge over the mid Atlantic region
and se states builds south. This pattern will continue to lead to a
light to moderate easterly flow through early next week with better
winds and seas occurring during the overnight and morning hours due
to a better thermal gradient setting up each night. Seas will
continue to range from 3 to 5 feet well offshore through Sun then
begin to subside slowly by early next week. 32/ee




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