577 
FXUS64 KMOB 212340 AAA
AFDMOB

Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
640 PM CDT Sun Jun 21 2020

.AVIATION...
00Z issuance...VFR conditions are expected to prevail through the
period, except for localized upper-end MVFR conditions in/near 
increasing convection on Monday between 22.16z and 22.24z. 
Southerly winds around 10 this evening will diminish to a light 
southerly flow overnight, and then increase again to around 10 
knots on Monday. /22

&&

.PREV DISCUSSION... /issued 340 PM CDT Sun Jun 21 2020/ 

NEAR TERM UPDATE /Now Through Monday/...A shortwave trof located mainly 
near the mid Mississippi River valley moves off to the east through 
tonight while a larger scale upper trof amplifies over the central 
states. The central states upper trof continues to amplify on 
Monday and also advance eastward slowly. A surface ridge remains 
over the northern Gulf and promotes a light southerly flow over 
the forecast area, and this pattern will continue a trend of 
improving deep layer moisture during the period, with precipitable
water values rising from 1.5-1.75 inches to near 2.0 inches on 
Monday. A weak sea breeze is expected to develop today which along
with daytime heating will support mainly isolated showers and 
storms to develop this afternoon and linger into the evening 
hours. MLCAPE values this afternoon will be near 1500 J/kg, and 
model soundings show some mid level dry air which will enhance 
downdrafts with the stronger storms. Following upon this, DCAPE 
values are near 1000 J/kg during the mid to late afternoon hours 
and indicates that strong wind gusts are certainly possible. As 
the central states upper trof begins to advance eastward, a series
of shortwaves will move across the region which when combined 
with a weak sea breeze in an environment with MLCAPE values of 
1500-2000 J/kg, will result in scattered to numerous showers and 
storms developing during the day. DCAPE values of 700-900 J/kg are
possible, and based on the current data it appears that 
precipitation loading looks to be the main initiating mechanism 
for downdrafts which will then be accelerated in the subcloud 
environment. Will continue to monitor for strong storm development
Monday afternoon. Lows tonight range from around 70 inland to the
mid 70s at the coast. Highs on Monday range from the lower 90s 
inland to the upper 80s at the coast. A low risk of rip currents 
continues through Monday. /29

SHORT TERM /Monday night Through Wednesday night/...An upper trough 
stretches south over the Mississippi River through Tuesday night 
before an upper ridge over the Gulf of Mexico/Caribbean begins to 
build west. This shifts the base of the trough from over the Lower 
Mississippi River Valley west to over the Southern Plains. With a 
very most airmass over the Southeast, and the proximity of the upper 
trough just to the west of the forecast area, a wet period is in 
store for the forecast area. Even after the upper trough begins to 
shift west Wednesday and Wednesday night, a series of upper 
disturbances move through the trough and east over the Southeast, 
extending the wet period into mid week. There is expected to be a 
downward trend in convection coverage overnight Tuesday and 
Wednesday nights with the loss of the day's heating, as limited as 
it will be. Local tools continue to advertise a moderate to high 
chance of strong downburst winds. Adding DCape into the equation, 
guidance continues to advertise values rising to around 700-900J/kg, 
especially Tuesday, adding to the strength of the downburst winds. 
Will continue to monitor as this period approaches.

With the widespread convection each day, high temperatures will be 
limited to below seasonal levels. High temperatures in the mid 80s 
to around 90 are expected Tuesday, low to mid 80s Wednesday over 
most of the forecast area. Overnight low temperatures will see 
around to a bit above seasonal norms with the decrease in overnight 
radiational cooling, ranging from around 70 well inland to low to 
mid 70s closer to the coast and upper 70s along the beaches.
/16

EXTENDED TERM /Thursday Through Sunday/...Thursday into the weekend, 
guidance is advertising the Gulf/Caribbean upper level ridge 
building north over the Southeast. Increasing upper subsidence will 
help to decrease the chance of convection through the Extended, even 
with the soupy airmass remaining in place, along with bringing an 
increase in daytime temperatures into the weekend. High temperatures 
Thursday are expected to range in the mid to upper 80s, with chance 
to low end likely (mainly west of the Alabama River) PoPs. By the 
weekend, high temperatures ranging from around 90 to the mid 90s are 
expected. Low temperatures through the period are expected to range 
from around 70 to low 70s north of Interstate 10 to mid/upper 70s 
south. 
/16 

MARINE...Locally higher winds and waves are possible near isolated 
to scattered showers and thunderstorms. Otherwise, no impacts are 
expected. /29

&&

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

$$

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