479 
FXUS64 KMOB 302252 CCA
AFDMOB

Area Forecast Discussion...Correction to Near Term 
National Weather Service Mobile AL 
404 PM CST Thu Dec 30 2021

.NEAR TERM UPDATE /Now Through Friday/...Tonight through Friday, our 
region remains in southwest flow aloft as our region remains on the 
western periphery of ridging that continues to stretch north along 
the East Coast. At the surface, ridging continues to nose into our 
region from the east, with the ridging stretching west over the Gulf 
of Mexico through the period. This results in a general south- 
southwest low-level flow over the forecast area through the period. 
Given this pattern the air remains nice and moist through Friday, 
and more prominent ridging on Friday will also keep temps nice and 
warm. 

In terms of sensible weather, conditions are expected to remain 
mainly dry tonight through Friday although a few very isolated light 
showers cannot be ruled out. Guidance suggests winds easing as any 
residual precipitation moves off to the east. With this, fog 
development is a concern for tonight. Currently there is a Dense Fog 
Advisory in effect for Coastal Mobile and Baldwin Counties in 
Alabama, and Coastal Escambia, Santa Rosa, and Okaloosa counties in 
Florida beginning at 10PM CST. Outside of this, fog is expected to 
move inland through the night with areas of fog (some locally dense) 
expected generally along and south of the Highway 84 corridor, and 
patchy fog (some locally dense) north of Highway 84. There is a bit 
of uncertainty on how widespread dense fog will be outside of the 
Dense Fog Advisory area, but depending on how trends play out it may 
be needed a bit further inland. Trends will be monitored and 
updated. 

As we remain in a warm and moist airmass through the near term, 
temperatures through the period remain anomalously warm. Lows 
tonight continue to generally be in the upper 60s to low 70s across 
the area. Any fog development along with mostly cloudy skies will 
help to keep temps on the warmer side. On Friday, not to sound like 
a broken record, but more records will likely be broken, as if we 
have not broken enough over the last couple days. Highs on Friday 
will likely be the warmest day on record in the month of December 
across the CWA with mainly low/mid 80s expected with some spots 
reaching the upper 80s. Lastly, a High rip current risk remains in 
effect through the period. JEH/88


&&

.SHORT TERM /Friday night Through Sunday night/...Strong southerly 
flow ahead of an approaching positively tilted upper level trough 
will continue to advect abundant low level moisture across the 
region Friday night. Very warm and humid conditions will persist 
with low temperatures remaining in the upper 60s interior to lower 
70s along the coast. Weak isentropic ascent within the moistening 
low levels will likely support the development of isolated to 
scattered showers overnight across much of the area. Another concern 
will be redeveloping sea fog Friday evening that will continue 
through Saturday morning. Dense fog is likely again to form near the 
coast and over bays and sounds as low 70s dewpoints overspread lower 
to middle 60s water temperatures. We will wait until tomorrow to 
reanalyze the specifics, but it does appear that another 
marine/coastal dense fog advisory will be needed. The fog potential 
may again develop Saturday evening but there is more uncertainty at 
this time. 

There still remains some disagreement with model timing and 
intensity regarding the handling of the approaching upper trough and 
associated strong cold front. It appears that much of the guidance 
has slowed and the frontal passage looks to occur from early predawn 
Sunday across western sections and early Sunday afternoon across the 
east. The latest guidance suggests that the positive trough begins 
to take on a more neutral tilt orientation as it passes through the 
area. This may result in an uptick in severe storm potential from 
Saturday night through early Sunday afternoon. At this time, it 
appears that there will likely be enough large scale forcing along 
the front to support a developing squall-line that will move into 
the western portions of our area later Saturday night and then to 
roughly the I-65 corridor by Sunday morning. Again, initially the 
best lift associated with the upper trough and right entrance region 
of a broad 140kt+ upper jet is aligned right along the front. This 
should limit prefrontal convection across the open warm sector 
initially. As the trough begins to rotate through and becomes 
increasingly neutrally tilted, there is some potential for 
prefrontal convection. There still remains uncertainty as to the 
exact storm mode, but this is our best estimate at this time. 
Abundant deep layer shear and sufficient instability should support 
the potential for some severe storms. Since there still remains some 
uncertainty regarding storm mode, it is still a bit too soon to pin 
down the greatest severe weather hazards. This will hopefully come 
into clearer focus as we get closer to the event and model 
differences get resolved. 

Behind the strong cold front, much colder temperatures will advect 
into the area on strong northwest winds. Temperatures will likely 
fall after the frontal passage later on Sunday. Strong cold 
advection will result in cold low temperatures by Monday morning 
which will be a stark change from the warm temperatures as of late. 
Lows will range from the middle 20s to the lower 30s along the 
coast. /JLH

&&

.EXTENDED TERM /Monday Through Thursday/...Weak upper ridging over the 
Plains shifts east through mid week, with surface high pressure that 
had moved over the Plains quickly moving east, to off the East Coast 
by Tuesday night. With a surface ridge stretching southwest over the 
Southeast, strong northerly winds shift to easterly Tuesday into 
Tuesday night. With the weak ridging bringing an increase in upper 
subsidence, temperatures well below seasonal norms Monday rise to 
around normal Tuesday. A shallow upper trough replaces the weak 
ridge over the Southeast Wednesday into Thursday, with the surface 
ridge weakening and shifting south to over the northern Gulf coast, 
returning southerly, albeit weak, flow to the Southeast. With weak 
onshore flow Wednesday through Thursday, moisture levels increase 
slowly, with guidance advertising precipitable h20 values rising 
from around 0.2" Monday to around 1.0" by Thursday. An upper level 
shortwave moves through the shallow upper trough over the Southeast 
Wednesday through Thursday, bringing a return of rain to the 
forecast area. With the weak nature of the both the passing 
shortwave and moisture return, rain chances will be on the low side, 
with slight chance to chance PoPs before a cold front moves across 
the forecast area Thursday night. Guidance is inconsistent with the 
southerly flow Wednesday on, with the operational ECMWF a bit 
stronger. The result is a bit wetter and warmer forecast as compared 
the GFS. Both are advertising above normal temperatures for 
Wednesday through Thursday, just more so with the ECMWF. For this 
portion of the forecast, have went with a blend, with the result 
being temperatures about 5 degrees above seasonal norms for the 
latter half of the Extended.
/16 

&&

.MARINE...A brief weakening in northeasterly to northerly winds 
today will increase back to Small Craft conditions through tonight 
as a surface low continues east across the central Gulf. Seas will 
remain elevated through the weekend before slowly subsiding through 
Tuesday, and then slowly increase again going into mid-week. Light 
to moderate winds will remain out of the northeast through the 
weekend before turning east then south-southeast by Tuesday. Wind 
speeds begin to pick back up by this time and Small Craft Exercise 
Caution conditions are possible again by this time. Conditions will 
continue to be monitored and updated as needed. JEH/88 

&&

.PRELIMINARY POINT TEMPS/POPS...
Mobile      68  82  71  81  69  69  29  52 /  10  10  20  50  80  50   0   0 
Pensacola   70  82  71  81  71  73  34  54 /  20  20  20  30  70  70   0   0 
Destin      70  80  73  80  72  76  38  56 /  20  30  30  20  70  80  10   0 
Evergreen   68  86  69  85  68  71  29  54 /  20  10  20  50  90  60   0   0 
Waynesboro  67  81  67  79  56  56  26  49 /  10  10  10  80  90  50   0   0 
Camden      66  81  67  82  63  63  28  50 /  10  20  10  60  90  60   0   0 
Crestview   69  83  70  80  71  75  31  54 /  20  20  30  30  70  80  10   0 

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...High Rip Current Risk through Sunday morning for ALZ265-266.

     Dense Fog Advisory from 10 PM this evening to 11 AM CST Friday 
     for ALZ265-266.

FL...High Rip Current Risk through Sunday morning for FLZ202-204-206.

     Dense Fog Advisory from 10 PM this evening to 11 AM CST Friday 
     for FLZ202-204-206.

MS...None.
GM...Dense Fog Advisory until 11 AM CST Friday for GMZ630>636-650-655.

&&

$$

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