572 FXUS64 KMOB 100009 AAA AFDMOB Area Forecast Discussion...UPDATED National Weather Service Mobile AL 709 PM CDT Mon Mar 9 2020 .NEAR TERM UPDATE /Now Through Tuesday night/...An upper level shortwave trough will move east over the Central Mississippi and Tennessee River Valleys tonight into Tuesday, along the north side of a weak upper ridge stretching north over the Southeast. Best combination of upper dynamics and moisture levels will be over northern portions of the forecast area, so best PoPs have been placed along and north of Highway 84 tonight through Tuesday. Lightening southerly flow and increasing moisture levels Tuesday night signal the return of overnight fog development. Water temperatures along and south of the coast have warmed into the lower 60s, but with warmer, moist Gulf air overflowing this relatively cooler water, an advection component is expected to add to fog development. Subsidence from the upper ridge will add to the warm southerly flow to bring above seasonal temperatures to the forecast area through the Near Term. Low temperatures in the upper 50s to low 60s expected tonight and Tuesday night. High temperatures in the mid 70s expected Tuesday. /16 && .AVIATION... 00Z issuance...General VFR conditions expected under southerly flow of 5 to 10 knots overnight though Tuesday. Passing shortwave energy will bring a chance of rain and temporary drops in CIGs to MVFR levels later tonight through Tuesday, mainly to areas along and north of Highway 84. /16 && .PREV DISCUSSION... /issued 344 PM CDT Mon Mar 9 2020/ NEAR TERM UPDATE /Now Through Tuesday/...A shortwave trof over the Plains ejects off across the interior eastern states tonight into Tuesday morning while an associated surface low brings a trailing cold front southward into northern Mississippi/northern Alabama Tuesday afternoon. A surface ridge over the southeastern states weakens somewhat ahead of the approaching front with southeasterly winds becoming southerly over the forecast area. Deep layer moisture increases through Tuesday with precipitable water values initially near 1.0 inch increases to around 1.3 inches by late tonight with similar values continuing into Tuesday. A combination of a series of weak shortwaves and deep layer lift associated with the southern fringe of the shortwave trof passing to the north will bring a region of modest deep layer lift mainly across the northern portion of the forecast area overnight into Tuesday morning. In response to this and with the increasing deep layer moisture trend, have continued with chance to good chance pops tonight along and north of I-65, with good chance to likely pops north of I-65 Tuesday morning and lesser pops further to the south. PoPs Tuesday afternoon are less certain, but it appears that a continuing series of weak shortwaves along with improving instability (SBCAPE values trending to 200-700 J/kg) will be sufficient to maintain good chance to likely pops north of I-65 while lesser pops continue elsewhere. Lows tonight will be mainly in the mid to upper 50s and highs on Tuesday will be 70 to 75. A high risk of rip currents continues through the period due to an onshore flow and onshore swell. /29 SHORT TERM /Tuesday night Through Thursday night/...The parade of weak shortwaves will continue to move through an otherwise bland and zonal upper pattern. At the surface, stout high pressure will be A shortwave trof over the Plains ejects off across the interior eastern states tonight into Tuesday morning while an associated surface low brings a trailing cold front southward into northern Mississippi/northern Alabama Tuesday afternoon. A surface ridge over the southeastern states weakens somewhat ahead of the approaching front with southeasterly winds becoming southerly over the forecast area. Deep layer moisture increases through Tuesday with precipitable water values initially near 1.0 inch increases to around 1.3 inches by late tonight with similar values continuing into Tuesday. A combination of a series of weak shortwaves and deep layer lift associated with the southern fringe of the shortwave trof passing to the north will bring a region of modest deep layer lift mainly across the northern portion of the forecast area overnight into Tuesday morning. In response to this and with the increasing deep layer moisture trend, have continued with chance to good chance pops tonight along and north of I-65, with good chance to likely pops north of I-65 Tuesday morning and lesser pops further to the south. PoPs Tuesday afternoon are less certain, but it appears that a continuing series of weak shortwaves along with improving instability (SBCAPE values trending to 200-700 J/kg) will be sufficient to maintain good chance to likely pops north of I-65 while lesser pops continue elsewhere. Lows tonight will be mainly in the mid to upper 50s and highs on Tuesday will be 70 to 75. A high risk of rip currents continues through the period due to an onshore flow and onshore swell. /29 centered over the western atlantic and nosing over the southeastern US. Southerly flow will continue at the surface and rain chances will likely increase with the passage of each shortwave. Rain chances will likely remain focused along and north of the highway 84 corridor where the best forcing is present. Luckily deep layer moisture is lacking and no substantial heavy rain threat is expected. A few rumbles of thunder will be possible each day, but with minimal cape storms will struggle. With the continued southerly flow at the surface, a high rip current risk will likely continue through the period. Along with rip currents, this setup is conducive for some coastal fog during the morning each day. Visibilities will likely be reduced to less than 1 mile in many locations Wednesday morning and possibly Thursday. Temperatures will be on a steady warming trend throughout the week as weak warm air advection persists. Highs will slowly climb into the mid to upper 70s by Thursday and some areas could reach 80 degrees. If the sun is able to peak through the clouds, temperatures could run even warmer. Lows will also be on the rise as low level moisture returns to the area. BB/03 EXTENDED TERM /Friday Through Monday/...By Friday, a strong upper ridge building over the western Gulf will being to slowly shift into the central Gulf in response to a digging trough over the western US. A weak cold front will drop down into the southeast on Saturday as the parent surface low moves across the Ohio River Valley. With the upper trough shearing out and the surface low racing to the northeast, the surface front will likely slow and stall as it reaches our area. This will allow for rain chances to increase again on Sunday, but the best areas of rain will be dependent on how far south the front makes it. A more zonal pattern will setup again as we head into next week which will lead to similar conditions to this week. Temperatures will continue to be on the warm side with the front likely stalling either over or just north of our area. BB/03 MARINE...Moderate to occasionally strong southeast winds gradually subside tonight. While the winds have decreased below 20 knots, will continue with the Small Craft Advisory for the near shore waters until 7 pm and until 1 am for the 20-60 nm portion to allow for seas to subside below 7 ft. Areas of fog are expected to develop over the bay and near shore waters Tuesday night then diminish Wednesday morning, but may redevelop again Wednesday night. Light southerly winds follow for Tuesday through Friday which become a light to moderate southeasterly flow on Saturday. /29 && .MOB WATCHES/WARNINGS/ADVISORIES... AL...High Rip Current Risk through Wednesday morning for ALZ265-266. FL...High Rip Current Risk through Wednesday morning for FLZ202-204- 206. MS...None. GM...Small Craft Advisory until 7 PM CDT this evening for GMZ650-655. Small Craft Advisory until 1 AM CDT Tuesday for GMZ670-675. && $$ This product is also available on the web at: http://weather.gov/mob