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357 FXUS64 KMOB 192104AFDMOBArea Forecast DiscussionNational Weather Service Mobile AL404 PM CDT Wed Mar 19 2025...New Discussion, Marine, Fire Weather....DISCUSSION...Issued at 400 PM CDT Wed Mar 19 2025Now through Thursday night...A medium amplified upper trough extending from the Upper Midwest to the southern Plains will reach the lower Mississippi River region late tonight. This trough will then pass over our area on Thursday, eventually reaching the southeast U.S. coast by late Thursday night. A low level ridge extending from the western Atlantic across the Florida Peninsula and into the eastern Gulf will maintain a light southwesterly flow this evening, then abruptly shift northwesterly as a strong cold front (associated with the upper trough) passes through the forecast after midnight, bringing a shot of cool and dry air as we head into Thursday with northwesterly winds prevailing. A Frost Advisory will likely be issued for Thursday night as lows look to range from 33 to 37 degrees interior areas, and from 38 to 43 degrees near the coast, or about 10 to 15 degrees below normal.A band of scattered to numerous showers with embedded non-severe isolated to low-end scattered thunderstorms will be moving across the area through tonight. A dry low-level air mass will mix down to the surface on Thursday, allowing surface dewpoints to lower to between 27 and 33 in the afternoon. The combination of this dry airmass mixing down and daytime high temperatures ranging from 60 to 65 degrees should result in relative humidity values dropping into the mid 20s to lower 30s. High temperatures on Thursday will average 8 to 14 degrees below normal, ranging from 58 to 63 degrees interior areas, with mid 60s near the coast. /22Friday through Wednesday...Friday into the weekend, an upper level trough over the East Coast moves off, with a second weak shortwave passing north of the forecast area Friday night. Weak upper ridging passes over the forecast area between the shortwaves, but a more zonal flow settles over the Southeast for the weekend. Another closed upper low moves east over the US/Ca border, passing well north of the Southeast Sunday through Monday, but directing a weaker shortwave system over the Southeast Sunday night into Monday night. A cold front moves southeast over the Southeast late Sunday through Monday in response, with a round of showers and thunderstorms returning to the forecast area Sunday afternoon through Monday. Into mid week, the closed upper system digs south over the East Coast, with an upper ridge building over the Plains. Looking more closely at weather through this portion of the forecast, the first item to deal with is possible frost Thursday night into Friday morning. A Frost Advisory will likely be needed to be issued in later shifts. The next item is the possibility of rowdy weather Sunday afternoon into Monday. Sunday afternoon into Sunday night is the first round. Moisture levels rise to around 1.5" over areas ahead of the advancing front. With the strongest upper dynamics well north of the forecast area, upper support is modest. Instability is also modest, with best values west of the forecast area, regardless of the model. GFS is advertising MUCapes rising to around 1000J/kg over south-central to southeast Mississippi (higher further west). Bulk Wind Shear around 35knots and Effective Shear around 25 kts is present. 0-1km helicities around 170m^2/s^2 are present. Looking at mid level lapse rates, most of the latest guidance is advertising 7.5C-8.0C, enough for hail. SPC has painted a 15% chance of severe weather to the west of the forecast area. For us, damaging winds and hail are the primary threats, mainly over and west of the Mississippi/Alabama state line Sunday afternoon through Sunday evening, weakening into the late evening overnight hours. As the cold front advances over the forecast area to near the Alabama River by 12z/7am Monday morning, the third item to deal with approaches. There exists a possibility of morning heating destabilizing the airmass over areas along and southeast of I-65 ahead of the front before the front moves south of the coast by 18z/1pm Monday. Bulk Shear around 45kts is present along and southeast of I-65, though instability advertised by the models is inconsistent (MUCapes around 300j/kg in the ECMWF to near 1000J/kg in the GFS at 15z Monday morn). Best mid level lapse rates for hail has moved south of the coast, so winds look to be the primary threat. Have less confidence of pinning down any rowdy storms Monday due to the inconsistency in the guidance.Looking at temperatures, high temperatures rise into the mid 70s to near 80 by Sunday. Behind the front's passage, high temperatures drop into the low to mid 70s Monday, then rise back into the mid to upper 70s for Wednesday. Low temperatures see the same roller-coast, rising from low to mid 40s over most of the forecast area Friday night to mid to upper 50s Sunday night. Low temperatures drop into the mid 40s to near 50 Monday night, then rise back into the upper 40s to mid 50s for Tuesday night.A low risk of Rip Currents is expected Friday into the coming week./16&&.AVIATION...(18Z TAFS)Issued at 1244 PM CDT Wed Mar 19 2025Lows clouds will increase from the west this evening as a line ofscattered to numerous light to moderate showers and isolated thunderstorms passes through the area overnight along a strong cold front. MVFR CIGS and VSBYS will accompany the precipitation,with very localized IFR CIGS and VSBYS possible near heavier showers and storms. Low-level wind shear from 310 degrees at 40-45knots to 2000 feet will occur in the wake of the front from midnight into early Thursday morning. South-southwesterly winds in the 10 to 15 knot range with gusts up to 25 knots will shift northwesterly late tonight. /22&&.MARINE...Issued at 400 PM CDT Wed Mar 19 2025The Small Craft Advisory for tonight into Thursday has been expanded in coverage to now include all of the bays and sounds across Coastal Alabama and the western Florida Panhandle as a northwesterly flow increases. Advisory conditions may taper over the bays and sounds by mid evening Thursday, but likely to continue into late Thursday night over the open Gulf waters. Winds gradually relax by Friday and a light onshore flow will be in place for the weekend. /22&&.FIRE WEATHER...Issued at 400 PM CDT Wed Mar 19 2025Drier upper level air is still in place Conditions are borderline for Thursday, both in winds and rh. Rh drops more for Friday, but winds decrease significantly. An RFW may be needed for Thursday, but am letting later shifts decide. /16&&.PRELIMINARY POINT TEMPS/POPS...Mobile 48 64 36 67 45 76 53 76 / 30 0 0 0 0 0 0 0 Pensacola 54 64 41 64 49 73 57 72 / 40 0 0 0 0 0 0 0 Destin 55 66 44 64 51 71 57 72 / 40 0 0 0 0 0 0 0 Evergreen 47 61 34 68 40 77 47 78 / 60 0 0 0 0 0 0 0 Waynesboro 43 61 33 69 42 77 49 80 / 40 0 0 0 0 0 0 10 Camden 46 57 34 67 42 74 48 78 / 50 0 0 0 0 0 0 10 Crestview 51 64 34 68 40 76 47 76 / 50 0 0 0 0 0 0 0 &&.MOB WATCHES/WARNINGS/ADVISORIES...AL...None.FL...None.MS...None.GM...Small Craft Advisory from 1 AM to 9 PM CDT Thursday for GMZ630>636. Small Craft Advisory from 1 AM Thursday to 3 AM CDT Friday for GMZ650-655-670-675.&&$$This product is also available on the web at:www.weather.gov/mob
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Topic: [Alert]MOB issues Area Forecast Discussion (AFD) at Mar 19, 4:04 PM CDT ...New Discussion, Marine, Fire Weather... (Read 487 times)
