169 
FXUS64 KMOB 030916
AFDMOB

Area Forecast Discussion
National Weather Service Mobile AL
416 AM CDT Sat Aug 3 2019

.NEAR TERM /Now Through Saturday night/...Currently, a weakly
organized  upper low is embedded in an upper trough stretching 
southwest across the Southeast and Lower Miss River Valley. In the
lower levels, weakly organized surface high pressure was analyzed
over the northern Gulf. On the radar, no echoes were noted over 
the forecast area, with most activity concentrated over Miss/SE La
Gulf waters in the late night hours. Last evening's upper air 
runs from neighboring sites show Precip H20 levels ranging from 
1.96" at KSIL to 1.64" at KBMX, below the levels indicated at the 
beginning of the model runs, especially the wetter NAM.

Today, guidance is consistent in the upper low getting absorbed in 
the upper flow of the upper trough and moving off. Best combination 
of available moisture and upper lift from the exiting upper low is 
over northeastern portions of the forecast area, so have painted 
best chance of rain these areas. Have went a bit below the wetter 
guidance with respect to rain coverage, especially with a bit drier 
airmass than models are indicating. Due to the greater coverage of 
rain and associated cloud cover, high temperatures today are 
expected to be limited to the upper 80s to around 90 over most of 
the forecast area, mid to upper 80s close to the coast. Looking at 
the chance of strong to severe storms, enough instability is present 
for some strong to marginally severe storms (MLCapes topping out in 
the 1000-1500J/kg range this afternoon). With limited wind shear and 
abundant moisture, wet downbursts look to be the primary mode of 
damage. 

Tonight, the thunderstorms will quickly decrease in coverage and 
intensity during the evening with the loss of the day's heat and 
instability, then shift offshore as overnight cooling creates an 
offshore land breeze. Lows around seasonal are expected, ranging 
from near 70 well inland to the low to mid 70s close to the coast.
/16

.SHORT TERM /Sunday Through Monday night/...A 50-60 knot upper
level jet rounding the northeastern quadrant of a large upper high
pressure system centered over the desert southwest will dive 
southward just west of the Mississippi River on Sunday. This will 
act to reinforce the 500mb trough extending from the lower Great 
Lakes region to the northern Gulf of Mexico. The upper trough will
then shift eastward toward the eastern seaboard on Monday and 
weaken slightly, while the upper high pressure remains in place.
 
Convection will primarily be diurnally driven, with daytime
surface heating bringing MLCape values into the 1000-2000 J/kg 
range both Sunday and Monday. Scattered to numerous showers and
thunderstorms will occur Sunday through early Monday evening, 
followed by decreased coverage Monday night as the trough moves
eastward. With the lack of dynamics, DCape values staying below 
800 J/kg, and wind shear nearly non-existent, no strong storms 
are anticipated. However, storm motion will remain erratic, and 
when combined with precipitable water near 2 inches, isolated 
prolonged rainfall and localized nuisance-type flooding will be 
possible. /22

.LONG TERM /Tuesday Through Friday/...A stronger upper level jet
of 70-100 knots exiting south central Canada Wednesday night will
dive southeastward on Thursday and push the upper trough off the 
eastern seaboard and over the western Atlantic. This will also
carve out a large trough over eastern Canada and the northeast 
conus. Meanwhile, the upper high will shift eastward, with an 
extension of an upper ridge building over the lower Mississippi 
River region and Gulf of Mexico through the remainder of the long 
term. Lower precipitation chances are expected through the period,
with mainly scattered convection Tuesday and Wednesday, followed
by isolated to low-end scattered coverage Thursday and Friday. We
will also see a slight increase in high temperatures through the 
long term due to stronger insolation. /22

&&

.MARINE...Weakly organized surface high pressure over the region 
will allow for an afternoon/evening onshore, late night into
morning offshore diurnal shift in winds through the weekend. As 
upper level high pressure builds west over the eastern Gulf early 
in the week, a more organized surface ridge builds west over the 
central/southern Gulf, bringing a more organized southwest, then 
westerly flow to area waters in the coming week. /16

&&

.PRELIMINARY POINT TEMPS/POPS...
Mobile      91  74  90  73  90  73  90  74 /  50  20  50  30  60  20  50  30 
Pensacola   90  77  89  77  89  76  90  76 /  40  20  40  30  60  50  40  40 
Destin      88  78  88  78  87  77  87  78 /  40  20  40  30  60  50  50  40 
Evergreen   92  73  91  73  90  72  92  72 /  60  30  60  30  70  20  40  10 
Waynesboro  90  71  89  71  89  70  91  71 /  60  40  60  30  60  10  30  10 
Camden      89  72  90  72  89  71  91  72 /  60  30  60  30  60  10  30  10 
Crestview   91  72  91  73  90  71  91  72 /  60  20  40  30  60  40  50  30 

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...None.
FL...None.
MS...None.
GM...None.
&&

$$

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