600 FXUS64 KJAN 071530 AFDJAN Area Forecast Discussion National Weather Service Jackson MS 1030 AM CDT Fri Oct 7 2022 ...New MESOSCALE UPDATE... .MESOSCALE UPDATE... Issued at 958 AM CDT Fri Oct 7 2022 No rain is in sight as dry weather conditions will continue to dominate our forecast area today. Current surface model analysis show the dry cold front currently digging across the Ohio Valley/Upper MS Valley and is forecasted to push towards our CWA later this evening. Current sounding observations support mixing in the lower levels. Compared to yesterday's sounding observations, the mixing level is much higher (somewhere around 750 mb). With this higher mixing level in place, a few cumulus clouds will appear later today. Daytime heating will lead to afternoon temperatures peaking in the upper 80s. Fire danger potential will be the main concern for today. Wind gusts are forecasted to gust up to 10 mph with higher gusts possible across the NW region. Due to this mixing, drier air will lower dewpoint temperatures and result in low RH values. Relative humidity (RH) values are projected to fall within minimum threshold between 30-35% with lower values forecasted across the Delta. A "Elevated" risk for the NW has been issued in the HWO for today and will continue until Sunday. The plan is to cover all areas with a "Limited" fire weather threat so that people take precautions over the weekend, and as additional burn bans are issued. /CRJ/ && .DISCUSSION... Issued at 352 AM CDT Fri Oct 7 2022 Today & tonight... Today: Shortwave ridging is situated over central-W TX with more stout upper low cutoff over the Desert SW & Baja Peninsula. Troughing is digging through the Great Lakes/Upper MS Valley, which will aid in a more significant frontal passage. Nearly 1040mb sfc high is situated over N Plains & the pressure gradient in the wake of the front today will help increase gradient winds across the region. Persistence fcst for highs is expected, with highs above climo in the mid-upper 80s. Isentropic ascent ahead of the cutoff low will keep some mid-high clouds around, which may inhibit some warmth. However, clouds should be thin enough to provide sufficient insolation to heat up. Main concerns will be the fire danger potential. With increased gradient winds & sufficient mixing/warmth, aftn humidity levels could bottom out near critical levels below 30%. With gradient winds up to 10-15mph possible, increased fire danger is expected. High KDBI & dry fuels coupled with gradient winds have prompted an increase to an "Elevated" for fire danger in HWO from along & NW of a line from Grenada-Yazoo City-Vicksburg, MS to Winnsboro, LA. This area has continually overachieved on mixing/low humidity & more recently on the winds. "Limited" area remains mostly the same but a small expansion in the SW along the MS River. This threat will continue into the weekend. Tonight: As trough swings into the Ohio Valley-NE, strong +1030mb sfc high pressure ridge will build into the central Plains to Mid MS Valley. Nearly 4 mb gradient will support winds remaining up overnight. This will keep lows only falling near climo in the low 50s in the Hwy 82 corridor to mid-upper 50s to the S. Broad isentropic ascent will keep some mid-high level cloudiness around overnight. /DC/ Saturday through next week... An upper shortwave responsible for pushing a dry cold front south through the area Friday night into Saturday morning will be moving east into the Mid-Atlantic with zonal upper flow and a much drier surface airmass left in its wake. We will notice much drier air through the day Saturday with highs in the lower 80s F south of I-20 and mid/upper 70s F north. This will allow relative humidity to fall into the 25-35% range in the north and west with gusty winds. For this reason, an elevated risk for fire weather was introduced into the Hazardous Weather Outlook (HWO) for Saturday, a continuation of the short term upward adjustment in risk outlook from today. Winds diminish into early Sunday morning with effective radiational cooling within the dry airmass under mostly clear skies. Overnight lows likely fall to near 50 along I-20 and 40s F to the north. Temperatures in the lower 50s are expected for the southern half of the area. Sunday afternoon will remain very dry under full sun and highs will climb into the mid/upper 70s east of I-20. Near and west of the Mississippi River, temperatures likely rise to near near 80 F. Regarding fire weather concerns, Sunday remains very dry and despite the somewhat lower winds, the additional drying will require the continuation of the elevated risk for fire weather in the Hazardous Weather Outlook (HWO) on Sunday as well for northern and western areas. Beyond Sunday, high pressure will remain in control with highs in the 80s F and lows mostly in the 50s F expected until midweek. Winds will begin to shift to southerly Wednesday into Thursday and this will allow some moisture recovery to be more apparent. Rain chances return Wednesday evening and especially Thursday as a stout upper shortwave trough rounds the base of a high amplitude long wave and pushes a well-defined cold front through our area. Without substantial surface cyclogenesis nearby, most of the upper dynamics to our north, and a narrow window for boundary layer recovery with southerly flow, strong to severe storms look unlikely as does flooding. Current guidance continues to suggest that what rain we do receive (and it doesn't appear to be drought busting amounts by any means with the most aggressive guidance suggesting amounts around 1 inch...) would be beneficial. With the stout front and cooler temps arriving aloft, some thunder may be possible though not explicitly defined in the gridded forecast. Timing, possible accumulations totals and additional event details will be refined over the next several days. /86/ && .AVIATION... (12Z TAFS) Issued at 646 AM CDT Fri Oct 7 2022 VFR flight cats with northerly winds, generally less than 15mph with brief higher gusts up to 15-20mph, are anticipated through the period. Dry front is expected to move through today, keeping northerly winds somewhat gusty into the aftn & lingering into the overnight hours. Winds will pick up similar again on Sat. Some few- sct cigs around 7-8kft are psbl, but most will be high cirrus. /DC/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 86 60 78 51 / 0 0 0 0 Meridian 86 57 77 48 / 0 0 0 0 Vicksburg 88 59 79 50 / 0 0 0 0 Hattiesburg 88 61 82 50 / 0 0 0 0 Natchez 87 61 80 53 / 0 0 0 0 Greenville 87 56 76 47 / 0 0 0 0 Greenwood 86 54 76 46 / 0 0 0 0 && .JAN WATCHES/WARNINGS/ADVISORIES... None. && $$ CR/LP/DC