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000 
FXUS64 KMOB 270244 AAA
AFDMOB

Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
944 PM CDT Mon Jun 26 2017

.DISCUSSION...Updated for latest aviation discussion below.

&&

.AVIATION...
06Z issuance...Mostly VFR conditions through 28.06z. Could see a 
brief period of MVFR cigs in and around an isolated shower or 
thunderstorm Tue afternoon. Winds will be mostly northeast to 
east at 3 to 8 knots through the forecast pd. 32/ee 

&&

.PREV DISCUSSION... /issued 634 PM CDT Mon Jun 26 2017/ 

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...
00Z issuance...Mostly VFR conditions through 28.00z. Could see a
brief period of MVFR cigs in and around an isolated shower or 
thunderstorm Tue afternoon. Winds will be northeast to east at 3 
to 8 knots through the forecast pd. 32/ee 

PREV DISCUSSION... /issued 359 PM CDT Mon Jun 26 2017/ 

NEAR TERM /Now Through Tuesday/...
A generally zonal mid level flow pattern prevails across our 
forecast area this afternoon on the base of a broad upper level 
trough that extends across much of the eastern CONUS. A surface 
ridge of high pressure meanwhile continues to build southward across 
the Mississippi and Tennessee Valley regions and into the central 
Gulf Coast states this afternoon. Area radars are detecting no 
precipitation across the area this afternoon, with visible satellite 
imagery only showing scattered to occasionally broken mid and high 
clouds moving overhead. A pleasantly drier airmass is in place over 
our area courtesy of the building surface ridge with dewpoints in 
the 50s to around 60 over most areas. The one exception is near the 
immediate coast where a weak seabreeze has developed, with light 
southerly winds bringing dewpoints up to near 70 around the Destin 
area. 

Little change to the overall pattern is forecast through the next 24 
hours. The broad upper trough does shift eastward some through 
Tuesday afternoon, but a general zonal to slightly northwest flow 
aloft continues over our area, while the surface ridge continues to 
build from the Ohio and Tennessee Valleys to the southeastern 
states. Mostly clear to partly cloudy skies are expected through the 
period. Dry weather is anticipated through Tuesday morning. Enough 
moisture convergence and instability may become available to aid in 
the development of isolated showers/storms along a weak seabreeze 
over the western FL Panhandle and portions of southwest AL by 
Tuesday afternoon, but POPs should be 20% or less. Lows tonight are 
forecast to range in the mid to upper 60s inland to 70-75 near the 
immediate coast and beaches. Highs Tuesday should warm to around 90 
inland with mid to upper 80s expected along the immediate coast and 
beaches. /21  

SHORT TERM /Tuesday night Through Thursday night/...
The upper trough axis along the East Coast of the country will move 
offshore Tuesday night into Wednesday. A weak northwesterly flow on 
the back side of the trough will likely keep weather conditions dry 
over most of the forecast area, as precipitable water values remain 
below seasonal normals for this time of year. Expect any (coastal) 
showers or thunderstorms to push offshore after sunset Tuesday as 
the flow aloft becomes increasingly zonal.

Boundary layer winds become more southerly for Wednesday, allowing 
low-level moisture to start its return. Even with a weakness 
remaining in the upper ridge over the northwestern Gulf of Mexico 
through Thursday, any convection is expected to be dominated by 
mesoscale processes (e.g., sea and bay breezes). This should allow 
greater odds for seeing showers and thunderstorms for mid-week, with 
the greatest coverage expected to be along and south of the US-84 
corridor Wednesday. Most of the convection should be diurnally 
driven, with any lingering showers or thunderstorms largely 
confined to coastal areas and offshore after sunset.

LONG TERM /Friday Through Monday/...
Weakness in the upper-level ridge weakens as it retrogrades into 
northeastern Mexico. This should allow broad ridging to continue 
over the southern U.S., with a more-or-less zonal pattern in place. 
The overall trend will indicate slightly warming afternoon 
temperatures as overall soil moisture continues to decrease. 

Regarding convection...I'm still struggling with a determination of 
convective coverage through the long term portion of the forecast. A 
generally subsident motion, thanks to broad ridging in place, will 
likely limit convective coverage somewhat. However, a shortwave 
trough is forecast to slightly amplify the flow by Day 6/7 as it 
dives toward the Upper Midwest. In addition, with low-level ridging 
centered in the Atlantic, southerly winds through the boundary layer 
should continue to deepen moisture over the region. There are some 
indications that precipitable water values may rise to 1 or 2 
standard deviations above climatological means by the weekend. 

All-in-all, it's a conundrum between subsidence and moisture. And 
given everything I'm seeing, I'll keep shower and thunderstorm 
probabilities in "chance" territory through the weekend, which is a 
skosh below blended guidance. /02/

MARINE...
Weak surface ridging is forecast to extend across the northern Gulf 
of Mexico through Tuesday night. A light to moderate offshore flow 
is expected to develop in the evening through early morning hours, 
with light to moderate onshore flow returning during the day, 
especially near bays and sounds. A light to moderate onshore flow 
becomes established Wednesday and continues into the weekend as 
surface high pressure becomes oriented from the western Atlantic to 
eastern Gulf of Mexico. /21

&&

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

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