National Weather Service Raw Text Product

666 
FXUS64 KMOB 072213
AFDMOB

Area Forecast Discussion
National Weather Service Mobile AL
413 PM CST Sun Jan 7 2024

...New NEAR TERM, SHORT TERM, LONG TERM, MARINE...

.NEAR TERM...
(Now through Tuesday Night) 
Issued at 413 PM CST Sun Jan 7 2024

Where to begin. Probably with the fact that with the current 
trends, we have leaned towards higher confidence in an extremely 
high impact event for our area. Very strong winds, potentially
moderate coastal flooding, high marine impacts and the potential
for a significant severe thunderstorm event including damaging 
winds and potentially a couple significant (EF-2+) tornadoes. 
Honestly when you put all the potential impacts together this 
could be one of the more impactful non- tropical systems we ever 
had. Take this system seriously! 


Synoptic Overview...A rather potent upper low will eject into the
Ohio River valley Monday into Tuesday night. The impressive nature
of this system continues to be represented within ensemble 
guidance with 500 Mb heights at a climatological min within the 
ECMWF, meaning this is an anomalously deep low. With anomalously 
deep lows usually come very strong jet dynamics and right now 
looking at a 110 to 120 knot jet streak developing around the base
of the upper low late Monday night into early Tuesday morning. 
Little further down a powerful 70 to 80 knot 850 mb jet will 
develop over our area during the same time and unfortunately 
trends within the higher resolution guidance have even hinted at 
increasing to 85+ knots. This is relatively rare territory even 
in some of our more impactful events. At the surface, these 
intense dynamics will allow for a powerful surface low to deepen 
into the upper 980s as it lifts across northeastern Arkansas. 
Expect rain to likely begin Monday afternoon as the synoptic warm 
front lifts northward and persisting throughout the overnight 
hours. Rain may become intermittent for a brief period before the 
final line of storms pushes through early Tuesday morning likely 
clearing out as we approach the noon Tuesday timeframe. Given how 
dynamic this system is we expect a plethora of hazards to come. 

Severe...Unfortunately, things trended the wrong way for us
amongst the high resolution guidance and the makings of a
significant severe thunderstorm threat appears on our doorstep. 
As mentioned in yesterdays afd, extreme environments tend to end 
in extreme results and the expected environment is quickly 
trending towards extreme. Going into yesterday the limiting factor
was the instability. As worried, the proximity to rich Gulf 
Moisture coupled with the intense low level wind field should have
no issued working instability inland across our area as the 
marine boundary lifts northward. All the high resolution guidance 
has around 1000 J/KG of MLCape making its way to the highway 84 
corridor with some guidance hinting at near 2000 J/KG near the 
I-10 corridor and has trended upward with time. Not great Bob, 
when that was suppose to be the limiting factor. On top of the 
instability the shear will be ludicrous with that 80 knot LLJ. 0-1
KM SRH values in the warm sector are hovering around the 500 to 
600 m2/s2 with insane low level curvature and high streamwise 
component. It would be immature to not at least mention that 
sometimes these shear environments can be too much especially with
lower amounts of instability much like last years; however, 
intense jet dynamics in the right entrance region of the upper jet
will likely overcome all of those issues. Expect two rounds of 
severe weather to be possible with both capable of significant 
severe. The first round is a little more conditional as 
instability and synoptic ascent will be more limited compared to 
round two. However, this round will be along the lifting marine 
boundary around midnight. This will likely involve embedded 
supercells lifting with the boundary leading to the potential for 
damaging winds and tornadoes. Given the shear environment and the 
boundary, a strong tornado cannot be ruled out. Then the real show
arrives shortly after and persists through the overnight in the 
form of a rather strong QLCS. This heavily forced squall line will
only intensify as the upper jet overspreads and the LLJ 
increases. The combination of strong kinematics and low level 
instability with 0-3km cape values likely approaching 100k/kg or 
more will support strong vertical stretching in a incredibly rich 
vorticity environment. QLCS tornadoes will likely be common with 
this line including the potential for a few strong QLCS tornadoes
(EF-2+). Along with the tornadoes, strong damaging winds will 
also be likely with wind gusts in excess of 70 mph given 850 and 
925 mb winds will already be high. This has the potential to be a 
rather intense severe event occurring overnight. Be sure to 
continue to stay updated and have multiple ways to receive 
warnings that are battery operated and charged as power may go 
out well before severe thunderstorms arrive. 


Beach/Coastal Hazards....Given the anomalously low pressures and 
tight gradient winds it will be outright howling across the marine
waters. Winds have only trended upward since yesterday. Given the
incredibly long fetch of strong winds, seas will quickly climb to
high surf warning criteria. Surf heights along the coast Monday 
night through Tuesday will likely approach 10 feet plus leading to
likely beach erosion, life threatening surf and rip currents and 
likely coastal overwash along flood prone barrier islands. On top 
of the intense wave action, strong low level winds will also push 
water leading to coastal flooding. Current PETSS guidance supports
at least solid coastal flooding and with current trends we are
quickly approaching coastal flood warning criteria Monday 
evening for Mobile Bay. For now the plan will be for a coastal 
flood advisory in the coming packages as confidence increases and 
we will have to monitor closely for a possible coastal flood 
warning. Nonetheless, the usual flood prone areas should expect at
least minor to possibly moderate coastal flooding and 
overwashing.


Wind Impacts...As if the rest of the discussion didn't spell it
out, it is going to be windy. Winds have trended upward with most
of the area likely seeing gusts up to 50 mph even as far inland as
highway 84. Along the coast winds will be peaked with gusts up to
60 mph possible as the strong low level jet and instability move
inland. A rather rare high wind warning has been issued for the
coastal areas with a high end wind advisory for the remainder of
the area. The compounding impacts of increased winds, weekend
trees from the last few months of drought and rainfall saturating
the soil will likely lead to trees coming down across the area. 
Power outages will be possible well before any severe 
thunderstorms arrive which could lead to a nasty combination. 
Charge battery powered methods of receiving warnings before going 
to bed and be sure to secure loose items outside. 


Heavy Rainfall Impacts...Confidence in rainfall happening is high 
but the heavy rainfall and flooding does It seem as likely 
outside of maybe a few urban areas. PWATS will steadily climb in 
advance of the system and elevated instability north of the 
lifting warm front Monday evening will allow for a shot for some 
heavier rain. The issues are 1. we are still dry from the last few
months. 2. the rather quick moving nature, especially with the 
second line could force things to be fully rate driven and not 
sure we get the rates long enough to overcome our relatively high 
flash flood guidance. If that first round of rain Monday evening 
is stronger and or the warm front gets hung up along the coast, 
then we might see some minor flash flood concerns develop. Right 
now the best area for heaviest rain is across southeastern 
Mississippi before the eventual squall line gets moving east. This
is honestly a rather low confidence flooding situation and will 
likely be driven heavily on the progression of the warm front and 
rain rates. 


All and all Monday night into Tuesday looks to be impactful for
our area with or without strong thunderstorms. The environment has
continued to come together the full gambit of impacts are becoming
likely. Keep up to date with this system as potential impacts may
change as we get more details. BB/03


&&

.LONG TERM...
(Wednesday through Sunday) 
Issued at 413 PM CST Sun Jan 7 2024

A negatively tilted upper trof over the northeast states moves well 
off to the north with a large upper trof meanwhile developing over 
the western CONUS by Thursday.  This next upper trof advances across 
the central states and amplifies while continuing into the eastern 
states on Saturday.  A ridge of surface high pressure builds into 
the forecast region on Wednesday then shifts off to the east on 
Thursday with light southwesterly winds gradually becoming 
southeasterly.  A surface low develops over the central Plains on 
Thursday in response to the western states upper trof, though after 
this point there is uncertainty with the trajectory of the surface 
low.  One possibility is for the surface low to move from the 
central Plains to the Great Lakes by late Friday night, while 
another possibility is for the surface low to shift into the south 
central states then move off to the northeast states on Saturday. 
Either solution brings a cold front through the forecast area at 
some point between Friday into Friday night, and the pattern overall 
supports chance to likely pops Thursday night, likely to categorical 
pops Friday, followed by dry or mostly dry conditions developing 
Friday night.  Despite the timing uncertainties, plenty of favorable 
shear looks to be available coincident with what appears to be 
sufficient CAPE values to indicate at least some potential for 
strong to severe storms.  This next event will need to be monitored 
closely.  Dry conditions are otherwise expected for Wednesday and 
Wednesday night, then from Saturday into Sunday. /29



&&

.MARINE...
Issued at 413 PM CST Sun Jan 7 2024

Light to moderate northeast winds become a moderate to strong 
easterly flow tonight. Gale to Storm Force conditions develop Monday 
then gradually diminish Tuesday night into Wednesday morning with a 
light to moderate westerly flow expected by Wednesday afternoon. 
Winds and seas will be higher near storms. /29



&&

.PRELIMINARY POINT TEMPS/POPS...
Mobile      41  67  51  62  33  53  38  64 /   0  90 100  50   0   0   0  10 
Pensacola   45  66  55  68  38  53  42  63 /   0  80 100  90   0   0   0  10 
Destin      46  66  57  70  41  56  45  65 /   0  80 100 100   0   0   0  10 
Evergreen   34  59  49  65  32  53  33  65 /   0  80 100  70   0   0   0  10 
Waynesboro  36  62  46  57  30  53  32  64 /   0  90 100  40   0   0   0  10 
Camden      34  56  47  62  32  50  32  61 /   0  80 100  60   0   0   0  10 
Crestview   36  61  54  67  33  54  34  64 /   0  80 100  90   0   0   0  10 

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...Wind Advisory from 4 PM Monday to 6 PM CST Tuesday for 
     ALZ051>060-261-262.

     High Wind Warning from 4 PM Monday to 9 AM CST Tuesday for 
     ALZ263>266.

     Coastal Flood Advisory from 6 PM Monday to 6 AM CST Tuesday for 
     ALZ263>266.

     Wind Advisory from 9 AM to 6 PM CST Tuesday for ALZ263>266.

     High Rip Current Risk from Monday morning through late Wednesday 
     night for ALZ265-266.

     High Surf Warning from 3 PM Monday to 7 AM CST Wednesday for 
     ALZ265-266.

FL...Wind Advisory from 4 PM Monday to 6 PM CST Tuesday for FLZ201-
     203-205.

     High Wind Warning from 4 PM Monday to 9 AM CST Tuesday for 
     FLZ202-204-206.

     Coastal Flood Advisory from 6 PM Monday to 6 AM CST Tuesday for 
     FLZ202-204-206.

     Wind Advisory from 9 AM to 6 PM CST Tuesday for FLZ202-204-206.

     High Rip Current Risk from Monday morning through late Wednesday 
     night for FLZ202-204-206.

     High Surf Warning from 3 PM Monday to 7 AM CST Wednesday for 
     FLZ202-204-206.

MS...Wind Advisory from 4 PM Monday to 6 PM CST Tuesday for MSZ067-
     075-076-078-079.

GM...Small Craft Advisory from 6 AM to 4 PM CST Monday for GMZ630>636.

     Small Craft Advisory from 9 AM Tuesday to 3 AM CST Wednesday for 
     GMZ630>636.

     Storm Warning from 4 PM Monday to 9 AM CST Tuesday for 
     GMZ630>636-650-655-670-675.

     Small Craft Advisory from 2 AM to 9 AM CST Monday for GMZ650-655-
     670-675.

     Gale Warning from 9 AM to 4 PM CST Monday for GMZ650-655-670-675.

     Gale Watch from Tuesday morning through late Tuesday night for 
     GMZ650-655-670-675.

&&

$$

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