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afdmob 


Area forecast discussion 
National Weather Service Mobile Alabama 
400 am CST Sat Nov 21 2009 


Short term (today and tonight)...latest WV/infrared loops depict surface low 
over the northwest Gulf south of iah and lch moving quickly eastward. To 
the southeast of the low center a warm front continues to emerge 
generally stretching southeast to east mostly over the central and southeast Gulf. 
To the north broad surface to 500 mb ridge over much of the middle Atlantic 
region and southeast Continental U.S. Continues to give way to cold air damming east 
of the Appalachians allowing main upper trough/low to track west of 
the Main Ridge axis later tonight...generally west of the 
Appalachians while attendant surface low over the western Gulf 
eventually departs to the east over the north central Gulf and 
begins to fill near or south of mob and pns later tonight. As a 
result surface warm front will move northward and stall south of the 
central Gulf Coast late this afternoon and tonight thus giving way 
to mostly elevated showers and thunderstorms near the coast and 
inland later this afternoon and tonight. Near the warm front 
generally just offshore a few rotating cells will be possible due to 
the strong vertical shear in the lower levels. Otherwise main 
concern over land through tonight looks to be heavy rainfall 
generally over the southern half of the County warning forecast area. As for temperatures will go 
slightly higher then mavmos near the coast today and stay close to 
the current 00z guidance for mins tonight. Will also back off on the 
wording in the severe weather potential statement about higher than normal tides and severe weather 
that was anticipated earlier in the week. /32 


Sunday through Monday night...with the GFS now having returned 
closer to the more reasonable and run-to-run stability of the European model (ecmwf) 
solution of the last several days...there is better agreement among 
the European model (ecmwf)/UKMET/GFS/Gem/NAM on the surface low moving generally 
across the coastal portion of the forecast area on Sunday then 
slowing and eventually dissipating through Monday as the associated 
shortwave/upper jet ejects off to the east-northeast. With dry air 
wrapping around into the system...will have chance probability of precipitation over the 
eastern and northern portion of the forecast area on Sunday then 
slight chance probability of precipitation over the southwest portion. Instability remains 
limited and looks like the only chance for an embedded thunderstorm 
will be over the Florida Panhandle with light rain otherwise 
prevailing. Not expecting any severe weather with this system. The 
layer lifted wrap around rains continue to decrease as the system 
weakens Sunday night and continues eastward...and will have slight 
chance probability of precipitation for light rain over much of the area Sunday evening then 
dry for the remainder of the night. Temperatures will be near 
seasonable levels. /29 


&& 


Long term (tuesday through friday)...a system over the northern 
plains occludes while moving across the Great Lakes through 
Wednesday and brings a weak cold front through the forecast area 
Tuesday into Tuesday night. Moisture continues to look just shy of 
being sufficient to support precipitation with the passage of the front and 
have stayed with a dry forecast. The occluded system continues off 
into Quebec through Wednesday night with a longwave trough moving 
across the eastern states through Friday and maintaining a deep 
layer dry northwesterly flow over the forecast area. After a 
somewhat mild day on Tuesday...temperatures will be at or slightly 
below seasonable levels through Friday. /29 


&& 


Aviation (12z issuance)...VFR conditions through early today 
followed by increasing low to middle level cloudiness with scattered 
areas of light to moderate rain with embedded showers and 
thunderstorms later today and tonight...moving mostly to the east 
northeast. A light to moderate northeast wind flow will build later 
today and early tonight becoming mostly north to northwest early 
Sunday morning. /32 


&& 


Marine...northerly winds and seas will build today and become 
mostly east early tonight in response to an area of low pressure 
tracking eastward over the marine area later tonight. Showers and 
thunderstorms are expected ahead of this system with few 
thunderstorms becoming strong at times generally along and south of 
a warm front which stalls over the marine area late this afternoon 
and tonight. As a result small craft should exercise caution through 
tonight. A light to moderate offshore flow will develop in the wake 
of the this system on Sunday and continue through midweek. /32 


&& 


Fire weather...very moist conditions today and Sunday trend drier 
through Tuesday but relative humidities remain well above critical 
levels. /29 


&& 


Preliminary point temps/pops... 
Mobile 61 51 64 49 / 90 80 20 10 
Pensacola 65 54 67 52 / 80 80 30 10 
Destin 68 58 69 56 / 60 80 40 10 
Evergreen 60 49 62 47 / 60 90 30 20 
Waynesboro 58 49 60 46 / 70 80 30 20 
Camden 61 49 59 46 / 40 80 40 20 
Crestview 61 51 69 49 / 60 90 40 20 


&& 


Mob watches/warnings/advisories... 
Alabama...none. 
Florida...none. 
MS...none. 
GM...none. 
&& 


$$