559 
FXUS64 KMOB 231632 AAA 
AFDMOB

Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
1132 AM CDT Sun Jun 23 2019

.DISCUSSION...See updated information for land areas below.

&&

.UPDATE...Shortwave ridging aloft is shifting eastward across
southwest/south central AL and the western FL panhandle this
morning, while southwesterly flow aloft is gradually spreading
into LA/MS ahead of a broad upper level trough over the Plains 
states. A shortwave impulse embedded within the southwesterly mid
level flow will lift northeastward toward southeast MS and
interior southwest AL this afternoon. Ascent associated with this
feature will interact with a moist (precipitable water values
around 1.8") and moderately unstable airmass (MLCAPE values around
2500 J/KG) to aid in the development of scattered showers and
thunderstorms across portions of southeast MS and interior
southwest AL this afternoon. High resolution convection allowing
models have been consistent in developing storms across this
portion of our CWA, so we have increased POPs generally along and
west of a Camden to Mobile line this afternoon. Our wet microburst
assessment does show a favorable potential for strong to locally 
damaging winds with any storm that develops across our western 
zones this afternoon, and we have kept mention in the Hazardous
Weather Outlook product. We also cannot rule out an isolated 
shower or storm over portions of south central AL (near Crenshaw/
Covington counties) in the vicinity of a weak surface boundary on
the southwestern periphery of a ridge located over the eastern 
CONUS. Otherwise, temperatures look on track to reach into the 
lower to mid 90s over interior areas, and around 90 near the 
beaches. Max heat indices will range between 100-105 this 
afternoon. 

Local beach reports from lifeguard partners indicate that rip
currents are most frequent over the FL panhandle beaches
(especially heading toward Destin) with the persistent
southwesterly flow and swell. We have lowered the rip current 
risk to MODERATE over the AL beaches, while keeping the HIGH risk 
over the FL panhandle beaches. /21

&&

.PREV DISCUSSION... /issued 609 AM CDT Sun Jun 23 2019/ 

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...
12Z issuance...Patchy fog across the area dissipates by mid
morning hours. VFR conditions and generally light south to
southwest winds expected through the forecast. A few isolated
showers and storms will be possible over southeast Mississippi and
southwest Alabama this afternoon and evening. Expect frequent
lightning and gusty winds in addition to locally lower cigs/vis in
and around the heavier storms. /49

PREV DISCUSSION... /issued 443 AM CDT Sun Jun 23 2019/ 

NEAR TERM /Now Through Sunday night/...A broad upper ridge 
builds into the eastern CONUS through the near term as an 
unseasonably deep longwave trough ejects from the Rockies eastward
over the Great Plains. At the surface, high pressure centered 
over the Florida peninsula and eastern Gulf maintains a south to 
southwesterly low- level wind flow across the region. While the 
strongest upper divergence associated with the upstream trough 
occurs over the Mississippi River Valley to our west, minor height
falls over the western half of the local area could provide 
enough of a weakness aloft for some isolated shower and 
thunderstorm development this afternoon and evening. This 
potential is only weakly supported in CAMs and SREF/HREF 
ensembles, likely due to a lack of forcing aside from diabatic 
heating. Given this uncertainty, decided to limited PoPs to slight
chance over southeast Mississippi and interior southwest Alabama 
counties. With convection heavily dependent on daytime heating, 
expect activity to taper after sunset this evening, with a dry 
forecast for our area tonight. Meanwhile, a broken line of 
thunderstorms is expected to organize well to our northwest over 
the Ark-La-Tex region extending northeast into western Tennessee. 
This line pushes southeast through central Mississippi during the 
overnight hours tonight as it gradually weakens. Even if 
convection dissipates before reaching the local area (as some 
guidance suggests), the remnant outflow boundary could serve as a 
focus for active weather in our area on Monday. See the Short Term
section below for more details. /49

SHORT TERM /Monday Through Tuesday night/...An upper ridge over
the Eastern Seaboard and eastern Gulf partially moves off into 
the western Atlantic through Monday night in response to an upper 
trof over the central states which takes on a negative tilt while 
moving off to the Great Lakes region. Scattered showers and storms
(possibly a broken line of convection) are expected to have 
developed west of the forecast area Sunday night in response to a
series of shortwaves moving through the base of the upper trof.
The forecast for Monday is a bit complex due to a weak outflow
boundary which is expected to have moved into the forecast area
from prior convection.  As the upper trof ejects off towards the 
Great Lakes, the scattered showers and storms advance into the
area along with potential additional convective development along
the weak remnant outflow boundary. Convective coverage is expected
to be better overall over the western portion of the area compared
to the southeastern portion where lingering subsidence effects 
with the upper ridge will be present, but this will have to be 
monitored. Have for now gone with good chance pops over the 
western portion which taper to slight chance pops over the 
southeast portion. A broad upper trof pattern forms over much of 
the eastern states Tuesday into Tuesday night while the axis of an
upper ridge persists just off the east coast and into the eastern
Gulf. Another upper ridge also advances eastward partially into 
the central states and begins to the amplify during this time 
frame. A series of shortwaves are expected to continue to move 
across the forecast area and expect isolated to scattered 
convective development by Tuesday afternoon with some convection 
lingering into the evening hours. Shear values will be low through
the period with 0-6 km bulk shear values typically less than 20 
knots. MLCAPE values of 1500-2500 J/kg develop on Monday then 
lower values are expected on Tuesday (1000-1500 J/kg) as somewhat 
drier lower level (900-800 mb) air is advected into the region. 
May see some strong storms develop on Monday given the higher 
instability, but otherwise severe storm development is not 
expected through Tuesday night. Highs each day will be in the 
lower 90s. Heat index values of 100 to 105 are expected on Monday 
with somewhat lower values expected on Tuesday. Overnight lows 
generally range from the lower 70s inland to the mid 70s at the 
coast. A high risk of rip currents is expected on Monday followed
by a moderate risk on Tuesday. /29

LONG TERM /Wednesday Through Saturday/...An upper ridge builds
over the central states while a weak upper trof develops over the
region and is expected to linger through Saturday. A surface ridge
will be located just west of the forecast area on Wednesday into 
Thursday which results in a seasonably unusual northerly surface 
flow over the forecast area. A weak inverted surface trof 
continues to be expected to meanwhile develop near the Florida 
peninsula/Florida Straits which then progresses slowly westward 
across the northern Gulf. This results in an easterly surface flow
developing over the forecast area on Friday which becomes
southeast on Saturday and brings increasing deep layer moisture
into the region. Have gone with mostly slight chance pops for
Wednesday then chance pops follow for Thursday as the upper trof
developing over the area provides for a better convective
environment despite a northerly surface flow. Chance to good
chance pops follow for Friday and Saturday as deep layer moisture
improves along with the inverted surface trof passing across the
area. Highs each day will be mostly in the lower 90s and overnight
lows range from around 70 inland to the lower/mid 70s closer to 
the coast. /29

MARINE...Surface high pressure gradually pushes west from the 
eastern Gulf into the north central Gulf and then lower Mississippi 
River Valley through the early part of this week. As a result, light 
to occasionally moderate southwest winds continue through Monday 
before gradually veering to westerly and then northerly by 
Wednesday/Thursday. No significant shower or thunderstorm activity 
is expected over the marine area until late in the week. /49

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...None.
FL...High Rip Current Risk through Tuesday morning for FLZ202-204-206.

MS...None.
GM...None.
&&

$$

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