MOB issues Area Forecast Discussion (AFD) at Jan 7, 4:36 PM CST ...New NEAR TERM, SHORT TERM, LONG TERM, MARINE...
696
FXUS64 KMOB 072237
AFDMOB
Area Forecast Discussion
National Weather Service Mobile AL
436 PM CST Tue Jan 7 2025
...New NEAR TERM, SHORT TERM, LONG TERM, MARINE...
.NEAR TERM...
(Now through Thursday)
Issued at 436 PM CST Tue Jan 7 2025
A very cold, dry airmass will continue to filter into the local
area through Thursday as a large Canadian high pressure system
slowly pushes southeastward. Even under mostly sunny skies during
the afternoons, highs for today will only top out in 40s, and
highs for tomorrow and Thursday will be in the upper 40s to low
50s. Lows for both tonight and Wednesday night will plummet into
the 20s areawide. A Cold Weather Advisory will be in effect from
midnight tonight through 9 am tomorrow across the entire area for
apparent temperatures (wind chills) in the 15 to 20 degree range.
Another advisory will likely be needed for Wednesday night for
similar wind chill values. /96
&&
.SHORT TERM...
(Thursday night through Friday)
Issued at 436 PM CST Tue Jan 7 2025
The most challenging part of the forecast comes during this brief
Thursday night and Friday period. Upper-level troughing extending
into the southwest US will begin to push eastwards during late
week. As it does so, strong diffluence aloft will overspread much
of the Southeast US. At the surface, a low pressure system is
expected to develop over the western Gulf on Thursday, quickly
lifting to the northeast through Friday. Latest model guidance
continues to agree that the low will move onto the MS coast late
Friday morning and will lift across our coastal counties
throughout the afternoon. Plenty of moisture and forcing will
allow for precip chances to increase rapidly throughout the
period. With no instability in place, expecting this event to
primarily be a widespread stratiform precip shield as opposed to
convection.
While confidence in precip chances remain high, precip type
(particularly in the Thursday night through Friday morning time
frame) continues to remain the main challenge of this forecast as
temperatures over the northern half of the CWA tumble into the low
to mid 30s. To understand what makes this forecast challenging,
let's break down the forecast sounding analysis (based on available
model guidance) for the northern CWA (Highway 84 corridor and
northward) into smaller time periods... note that at this time, rain
is the only precip type expected for locations south of Highway 84:
Start of Thursday evening (~10.00Z)- Forecast soundings in the
dendritic growth zone are beginning to saturate, while the surface
to 700mb layer remains rather dry. Temperatures within this dry zone
are above freezing, however, the wet bulb profile remains below
freezing for the entire sounding. This would suggest that non-
accumulating snow flurries would be the primary precip type,
however, with the best forcing still to our west and the profile
remaining rather dry at this point, not expecting precip to be
ongoing at this time.
Late Thursday evening into early Friday morning (03Z-09Z) - The
better forcing and moisture begins moving into the area from the
southwest and precip chances begin to increase. At the same time,
as the surface low starts to approach the area, a low-level jet
will begin to develop and move into the area. This will support a
warm air advection regime, especially in the 850 to 700 mb layer.
The result will be the development of a roughly 100-150 mb deep
warm layer that peaks at around 3-5C. On the flip side, the onset
of precip will begin to saturate the dry layer, allowing for temps
and dew points to approach the wet bulb temperature. Now with
warm air advection starting, the wet bulb temperature should begin
to slowly increase. That being said, a sub-freezing layer may
still exist somewhere above the surface and below the 850 mb level
(especially during the onset of precip). Surface temperatures at
this point look to hover around 32-34 degrees which would limit
any freezing rain potential. At this point, we believe that a cold
rain will be the primary precip type, but with the possibility of
a lingering sub-freezing layer, a mix of rain, sleet, and snow is
possible. To match our reasoning, have went with likely to
categorical rain chances, with a slight chance to chance of sleet
and snow mixing in for these northern areas. Once again, due to
surface temperatures remaining just above freezing and the warm
nose aloft being rather stout, any frozen precip that does occur
should not accumulate. We will monitor temperature trends closely
over the coming days.
Early Friday morning into mid Friday morning (09Z-14Z): Warm air
advection will continue to slowly warm the profile. Any remnant sub-
freezing layer should begin to erode and all precip should begin
transitioning to a steady, cold rain. Timing of when this full
transition occurs is of very low confidence and therefore a
lingering slight chance of sleet and snow remains for these northern
areas to account for timing uncertainties. Once the transition
occurs, the frozen precip threat has ended.
Remainder of the period (14Z-00z): The entire layer from 700mb to
the surface will be above freezing and no frozen precip is expected
by this point. /96
&&
.LONG TERM...
(Friday Night through Tuesday)
Issued at 436 PM CST Tue Jan 7 2025
The Longer term starts off with a positive tilt long wave upper
trof axis aligned from the Great Lakes, southwest to Cabo San
Lucas Friday evening with a fairly active high level southwest
flow ahead of it taking a zone of deep moisture and larger scale
ascent eastward into the southeast US. At the surface, a wave of
frontal low pressure will be moving over the western FL Panhandle
and southeast AL Friday evening, lifting quickly up across the
Carolinas Saturday AM. Rainfall ends from west to east in the wake
of the low and frontal passage Friday night. High pressure moving
east over the deep south supports a rainfree pattern over the
weekend. A nearly zonal (west to east) flow at high levels sets
up early next week. There is a signal for deeper moisture and
perhaps an increase in rain chances to spread eastward out of
Texas to out over the Gulf. The northern extent may ease near the
coast to generate a low PoP early next week.
Nights remain cold. Coldest day Saturday with highs in the 40s
looking to be some 11 to 16 degrees below normal. 50s Sunday and
Monday, perhaps tempered back again by Tuesday as cloud cover
thickens. /10
&&
.MARINE...
Issued at 436 PM CST Tue Jan 7 2025
Moderate northerly flow will continue through Wednesday night.
Winds will shift to easterly by Thursday night. By Friday, a storm
system will pass along the Gulf Coast bringing a strong onshore
flow and building seas to the marine zones. A Small Craft
Advisory will likely become necessary from the Friday through
Saturday morning timeframe. Winds quickly return back to an
offshore flow by the weekend in the wake of a cold front. /96
&&
.PRELIMINARY POINT TEMPS/POPS...
Mobile 26 49 25 50 38 56 33 48 / 0 0 0 0 60 100 40 0
Pensacola 30 50 29 50 42 60 38 48 / 0 0 0 0 40 90 60 10
Destin 33 51 32 52 44 60 40 51 / 0 0 0 0 20 80 70 10
Evergreen 24 48 23 49 32 49 31 45 / 0 0 0 0 50 100 50 0
Waynesboro 23 46 21 47 33 43 28 43 / 0 0 0 0 80 100 20 0
Camden 23 45 20 46 32 44 27 42 / 0 0 0 0 60 100 50 0
Crestview 25 51 23 50 33 54 35 48 / 0 0 0 0 30 90 70 10
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...Cold Weather Advisory from midnight tonight to 9 AM CST
Wednesday for ALZ051>060-261>266.
FL...Cold Weather Advisory from midnight tonight to 9 AM CST
Wednesday for FLZ201>206.
MS...Cold Weather Advisory from midnight tonight to 9 AM CST
Wednesday for MSZ067-075-076-078-079.
GM...None.
&&
$$
This product is also available on the web at:
www.weather.gov/mob
Source: MOB issues Area Forecast Discussion (AFD) at Jan 7, 4:36 PM CST ...New NEAR TERM, SHORT TERM, LONG TERM, MARINE... (https://mesonet.agron.iastate.edu/p.php?pid=202501072236-KMOB-FXUS64-AFDMOB)
---------------
If I'm using your data in a way that is against your terms please email the team at "threatweb@pupswoof117.com"! I am a bot who will not respond in the comments at all and is only designed to post RSS feeds!