Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

000 
FXUS64 KMOB 240559 AAA
AFDMOB

Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
1259 AM CDT Fri Mar 24 2017

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

&&

.AVIATION...
06Z issuance...MVFR to VFR cigs through 25.06z. Winds will
be southeast mostly at 12 to 16 knots through the forecast period
with gusts between 18 and 28 knots from mid morning through late 
afternoon. 32/ee

&&

.PREV DISCUSSION... /issued 630 PM CDT Thu Mar 23 2017/ 

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...
00Z issuance...Will begin with prevailing VFR conditions except
for a few spots near the coast where MVFR ceilings will be
present. MVFR ceilings are expected to develop across the western
half of the area overnight, with primarily VFR conditions 
expected over the eastern portion. MVFR ceilings may improve to
near VFR by midday over the western portion of the area as breezy
and gusty southeast winds develop. /29

PREV DISCUSSION... /issued 254 PM CDT Thu Mar 23 2017/ 

NEAR TERM /Now Through Friday/...Another 24 hours or so before we 
get a weather pattern change. Tonight through Friday the surface 
ridge will continue to ridge in across our area from the northeast, 
providing a continued mainly southeast low level windflow across the 
region. This moist onshore flow will result in a gradual increase
in low/mid cloud cover as the Gulf marine layer works its way 
further inland in conjunction with increased 850-700mb flow out of
the south provides increasing isentropic lifting over the area. 
Although we will be seeing an increase in clouds, overall not a 
noticeable increase in rain chances across most of the area 
through Friday, although we do indicate a slight chance for 
showers over our westernmost counties where deeper moisture and 
slightly better forcing is expected. Nighttime temperatures are 
still expected to run about 10-12 degrees above normal for this 
time of the year tonight, ranging from the mid/upper 50s over 
interior northeast zones to lower 60s coastal and southwest zones.
Friday's daytime temperatures are expected to be above, but 
closer to normal, with highs in the mid to upper 70s over inland 
areas and in the lower 70s at the coast. 12/DS 

SHORT TERM /Friday night Through Sunday night/...Forecast
geo-potential height fields start off with an amplifying upper
level trof moving over the plains with a downstream, short-wave 
mid level ridge over the southeast Friday night. The upper trof 
makes a steady eastward progression out of the Plains on 
Saturday. East of the upper trof, high level flow becomes 
increasingly diffluent favoring an increase in large scale deep 
layer ascent which spreads east over the forecast area ahead of a 
cold front moving into the Lower River Mississippi River Valley 
Saturday. Co-located with the larger scale ascent will be an 
improvement in deep Gulf moisture, where pwat values lift to 
around 1.35" along the Central Gulf coast. Organized storms are 
forecast to move eastward over the ARK-LA-TEX Friday night and 
looks to spread east across the local area on Saturday. The latest
forecast remains mostly unchanged maintaining highest chances of 
showers/storms occurring on Saturday. Given assessment of 
atmospheric instability, moisture, and lift, it appears we will be
dealing with the potential for some strong to a few severe storms
Saturday with the better potential for this looking to occur over
the northwest half of zones as these areas may be more influenced
by the tail end of a departing, stronger low level jet streak. 
Dynamics lift northeast and threat diminishes by Saturday evening.
There are uncertainties in amount of instability between the 
latest weather models, but think there will be enough to maintain
a slight risk of severe storms Saturday for much of the area. The
main threat looks to come from localized damaging winds along 
with marginal severe hail potential. Locally heavy rains will be 
possible with the passage of the stronger storms, but the expected
steady eastward progression would mitigate widespread flooding 
concerns. Will maintain a chance of showers and few storms 
Saturday night as axis of upper trof passes across. Despite lead 
feature lifting well away, moving northeast over the Appalachians 
and Ohio River on Sunday, a high level southwest flow is 
maintained. Out of respect for subtle impulses embedded in these 
type flows aloft, will carry a slight chance of showers/storms for
Sunday. Next upper level storm system moves eastward out of the 
Plains Sunday night. 

Unseasonably warm days and nights continue in the short term. /10

LONG TERM /Monday Through Thursday/...The passage of next upper 
level storm system brings return chance of showers and storms 
Monday and Monday night. Eastward building mid-level ridge over 
the southern US by Tuesday night supports rain-free conditions 
into Wednesday. The latest 23.12Z run of the ECMWF is quicker at 
bringing yet another storm system east and thus next potential 
round of showers/storms into the Lower Mississippi River Valley 
during the day Thursday, with the GFS slower. Will lean to the 
ECMWF solution which is also consistent with the latest National 
Blend of Models (NBM). Unseasonably warm days and nights look to 
continue thru the medium range. /10

MARINE...An area of high pressure will build over the Mid-Atlantic 
and western Atlantic through late week, ridging back to the southwest
over the eastern Gulf of Mexico. An area of low pressure developing
over the Plains through the end of the week will lift to the 
Great Lakes area over the weekend, with an associated trof moving
east across the marine area on Saturday. As a result, a moderate 
to strong onshore flow and resultant building seas will develop 
through late week, along with increasing chances of showers and 
thunderstorms by Saturday. A Small Craft Advisory is now in effect
for portions of the Marine Area from this afternoon through late 
Friday night. Through most of next week, the predominately 
moderate (occasionally strong) onshore flow will continue as 
several more weather systems pass just to the north of the marine 
area. 12/DS 

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...None.
FL...None.
MS...None.
GM...Small Craft Advisory until 1 AM CDT Saturday for GMZ631-632-650-
     655-670-675.

&&

National Weather Service Glossary of Abbreviations