Small Craft Advisory 24, NWS Mobile, AL

Area Forecast Discussion
National Weather Service Mobile AL
411 AM CDT Fri Apr 12 2019

.NEAR TERM /Now Through Friday night/...A surface low currently
located over the Upper Midwest continues to lift north into
eastern Canada through the near term. A cold front associated with
this low currently moving through central Mississippi weakens and
eventually stalls roughly along the I-65 corridor tonight. A few
showers and thunderstorms are expected today and tonight along
this front. Best rain chances will be over southeast Mississippi
and interior southwest Alabama counties, but included at least a
slight chance farther east to I-65 where a few isolated to widely
scattered cells could also develop. There is no severe threat with
storms today or tonight, but the persistent onshore flow ahead of
the front has led to a moderate risk for dangerous rip currents
along all area beaches. High temps reach the low to mid 80s inland
and upper 70s closer to the coast this afternoon. Lows tonight
remain mild due to increasing moisture and thick cloud cover, with
temps staying in the low to mid 60s inland and upper 60s along
the coast. /49

.SHORT TERM /Saturday Through Sunday night/...Active weather is
expected over the region during the period as an upper trof over
the central states/northern Mexico advances across much of the
eastern states with an associated surface low lifting from
southern Texas to the extreme northeast states. As the system
approaches, a squall line is expected to develop roughly along
the lower Mississippi river valley late Saturday afternoon into
the early evening hours. The squall line advances eastward into
the mid section of the forecast area late Saturday night into
early Sunday morning, then continues quickly through the
remainder of the area during the remainder of the morning hours.
Despite the timing of the line moving through the area during the
late night and morning hours, MLCAPE values of 750-1300 J/kg will
be present along and ahead of the squall line. An 850 mb jet near
50 knots will be present as well producing 0-1 km helicity values
of 200+ m2/s2, which when combined with the instability yields
Sig Tor values of 3, possibly 4, portending a potentially
significant severe weather event. Very high amounts of deep layer
moisture will be present with the squall line (precipitable water
values near 2 inches) indicating that locally heavy rain will
likely accompany the convection. While very high amounts of deep
layer moisture will be present with the squall line, mid level dry
air will also be present well ahead of the line with wet bulb
zero values potentially as low as 9 kft. Should convection develop
ahead of the convective line in this environment, there will be
the potential for strong wind gusts and also hail with the
stronger convection, potentially reaching severe limits. The
limiting factor for this leading convection is that outside of the
squall line, forcing does not appear to be all that impressive,
at least at this time.

Slight chance to chance pops on Saturday will be followed by
categorical pops shifting eastward across the area Saturday night
into Sunday morning as the squall line moves through.  A strong
cold front moves through the area in the wake of the squall line
bringing dry conditions for the rest of the period. A high risk of
rip currents is expected for Saturday and Sunday along with heavy
surf, and a wind advisory may become necessary beginning Saturday
afternoon. /29

.LONG TERM /Monday Through Thursday/...In the wake of the upper
trof, broad upper ridging builds into the region through Tuesday.
A surface ridge builds into the forecast area on Monday, then
shifts east of the area on Tuesday allow for a return flow to
ensue.  Another upper trof advances into the central states on
Wednesday then continues into the eastern states on Thursday. A
surface low develops to the lee of the Rockies over the central
Plains in response, and strengthens significantly while moving to
near the Great Lakes on Thursday, meanwhile bring a strong cold
front through the forecast area. Will have dry conditions through
Tuesday night then pops increase to chance areawide Wednesday into
Wednesday night and continue into Thursday. Will need to monitor
this next system for the potential of strong (severe?) storm
development Wednesday night into Thursday as instability and
shear look elevated (MLCAPE 1500 J/kg Helicity 200 m2/s2). /29

&&

.MARINE...Onshore flow strengthens tonight through Sunday morning as
a strong cold front approaches from the west. Seas build to 5 to 8
feet near shore and 7 to 10 feet well offshore by Sunday. Strong
westerly flow follows in the wake of the front Sunday afternoon and
evening before shifting to northerly and gradually diminishing
Monday morning. There is a Small Craft Advisory in effect for Gulf
waters and area bays and sounds beginning Saturday morning and
lasting through early Monday morning. Some storms along the cold
front on Sunday could be strong to severe. A generally light
offshore flow on Monday shifts back to southeasterly Tuesday and a
moderate onshore flow then prevails through the middle part of next
week. /49

&&

.PRELIMINARY POINT TEMPS/POPS...
Mobile      79  66  80  67  76  45  74  49 /  10  20  40  90  50   0   0   0
Pensacola   77  67  81  69  78  50  74  54 /  10  20  20  70  90   0   0   0
Destin      73  67  79  71  77  53  73  56 /  10   0  10  30  90  10   0   0
Evergreen   82  63  83  68  79  44  73  45 /  20  10  20  70  80  10   0   0
Waynesboro  80  63  81  65  74  43  73  48 /  40  30  40  90  30  10   0   0
Camden      82  64  82  67  78  45  72  47 /  30  30  30  80  70  10   0   0
Crestview   82  63  84  66  80  44  75  45 /  10  10  10  40  90  10   0   0

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...High Rip Current Risk from late tonight through late Sunday
     night for ALZ265-266.

     High Surf Advisory from 1 PM Saturday to 5 AM CDT Monday for
     ALZ265-266.

FL...High Rip Current Risk from late tonight through late Sunday
     night for FLZ202-204-206.

     High Surf Advisory from 1 PM Saturday to 5 AM CDT Monday for
     FLZ202-204-206.

MS...None.
GM...Small Craft Advisory from 10 AM Saturday to 7 AM CDT Monday for
     GMZ630>636-650-655-670-675.

&&

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

This product is also available on the web at:
http://weather.gov/mob

Hazardous Weather Outlook...UPDATED
National Weather Service Mobile AL
1025 PM CDT Thu Apr 11 2019

ALZ051>060-261>264-FLZ201-203-205-MSZ067-075-076-078-079-130330-
Choctaw-Washington-Clarke-Wilcox-Monroe-Conecuh-Butler-Crenshaw-
Escambia-Covington-Mobile Inland-Baldwin Inland-Mobile Central-
Baldwin Central-Escambia Inland-Santa Rosa Inland-Okaloosa Inland-
Wayne-Perry-Greene-Stone-George-
1025 PM CDT Thu Apr 11 2019

This Hazardous Weather Outlook is for south central Alabama,
southwest Alabama, northwest Florida and southeast Mississippi.

.DAY ONE...Tonight.

Patchy dense fog will develop across the area tonight.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

Strong to potential severe storms and perhaps locally heavy rains
possible late Saturday night into Sunday. At this time, it appears
the main threats in any severe storms will be damaging winds and
perhaps a few tornadoes.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this weekend.

ALZ265-266-FLZ202-204-206-130330-
Mobile Coastal-Baldwin Coastal-Escambia Coastal-Santa Rosa Coastal-
Okaloosa Coastal-
1025 PM CDT Thu Apr 11 2019

This Hazardous Weather Outlook is for southwest Alabama and
northwest Florida.

.DAY ONE...Tonight.

Patchy dense fog will develop across the area tonight.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

Strong to potential severe storms and perhaps locally heavy rains
possible late Saturday night into Sunday. At this time, it appears
the main threats in any severe storms will be damaging winds and
perhaps a few tornadoes.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this weekend.

GMZ630>636-650-655-670-675-130330-
Northern Mobile Bay-Southern Mobile Bay-Mississippi Sound-
Perdido Bay-Pensacola Bay System-Western Choctawhatchee Bay-
Eastern Choctawhatchee Bay-
Coastal waters from Pensacola FL to Pascagoula MS out 20 NM-
Coastal waters from Okaloosa Walton County Line FL to Pensacola FL
out 20 NM-Waters from Pensacola FL to Pascagoula MS from 20 to 60 NM-
Waters from Okaloosa Walton County Line FL to Pensacola FL from
20 to 60 NM-
1025 PM CDT Thu Apr 11 2019

This Hazardous Weather Outlook is for the coastal waters of Alabama
and northwest Florida.

.DAY ONE...Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

Onshore flow strengthens resulting in building seas going into the
weekend. Small craft advisories will likely become required. Strong
to potential severe storms possible late Saturday night into Sunday.
The potential also exists for the passage of locally heavy rains to
reduce visibility to a mile or less at times late in the weekend.