Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Mobile Alabama
1132 am CDT Sat Oct 22 2016
Discussion...see updated information for land areas below.
Update...high pressure continues to build into the area with a
cooler and much drier airmass continuing. Minor changes were made to
hourly temps based on the observations, otherwise no other updates
are needed at this time. /13
Previous discussion... /issued 619 am CDT Sat Oct 22 2016/
Discussion...updated for latest aviation discussion below.
12z issuance...VFR conditions expected through the forecast.
Previous discussion... /issued 436 am CDT Sat Oct 22 2016/
Near term /now through Saturday night/...as an upper trough over the
eastern conus swings east, a surface ridge stretching north along The
Rockies shifts east also. This shifts a surface high from over the
lower Mississippi River valley eastward, to over the southeast. This
will bring a lighter, more variable flow to the area, along with
enhancing the dry airmass over the southeast.
For the forecast, even with the approaching upper ridge, cooler
northerly flow will limit temperatures today to around seasonal, low
70s north to mid 70s south. For tonight, with the dry airmass being
maintained, a long with surface flow becoming light, excellent
radiational cooling will allow temps to fall to well below seasonal.
Mid 30s north to low 40s closer to the coast. Isolated frost may
even be possible north of Highway 84. /16
Short term /Sunday through Monday night/...surface high pressure and
the dry conditions will persist across the region through the short
term. A very weak upper level shortwave early next week will bring a
thin cirrus shield over the region Sunday and Monday. Otherwise we
will see a gradual warming trend through the period.
High temperatures Sunday will be back above normal, ranging from 76
to 81 degrees. Lows Sunday night will range from 43 to 49 degrees
inland areas, and from 50 to 55 degrees along the coastal sections
with upper 50s at the beaches. High temperatures Monday will be 2 to
3 degrees warmer. /22
Long term /Tuesday through Friday/...upper high pressure over the
Gulf of Mexico with an upper ridge extending northwestward over the
nation's midsection will shift eastward and weaken through mid week
as an upper shortwave moves over the plains to the Mississippi River.
The European model (ecmwf) and GFS models diverge in there solutions late next week as
the European model (ecmwf) lifts the shortwave northeast followed by an upper ridge
rebuilding over the deep south, while the GFS develops an upper cut-
off low over the Midwest that dives southward over the region. Will
lean toward the more progressive and drier European model (ecmwf) solution for now as
the GFS has had a tendency lately of forming cut-off upper lows in
the long term that never occurred.
A continuation of the dry period to the region is expected through
mid week, followed by our best chance of rain Wednesday night and
Thursday as the upper shortwave just reaches the forecast area. Only
expecting a 20 percent chance of precipitation north of I-10, with a
30 percent chance along the coast on Thursday, below drying out again.
High temperatures ranging from 78 to 83 degrees will occur Tuesday
through Friday. Low temperatures will mid 50s to lower 60s inland
areas Tuesday night through Friday night, with mid 60s along the
Marine...surface high pressure will shift east, to over the
southeast, bringing a lighter along with more easterly flow to area
coastal waters. A more diurnally driven daytime onshore/ night time
offshore flow returns for Sunday. A second surface high combines with
the southeastern conus surface high, bringing a return of generally
northerly flow Tuesday, then easterly as the surface high pushes to
the East Coast through mid week. /16
Florida...red flag warning until 6 PM CDT this evening for flz201>206.
Fire Weather Watch Sunday afternoon for flz201-203-205.
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