Area Forecast Discussion
Issued by NWS Memphis, TN
Issued by NWS Memphis, TN
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263 FXUS64 KMEG 050436 AFDMEG Area Forecast Discussion National Weather Service Memphis TN 1136 PM CDT Thu Jul 4 2024 ...New AVIATION... .UPDATE... Issued at 905 PM CDT Thu Jul 4 2024 00Z upper air analysis still shows an upper-level ridge present across the Lower Mississippi Valley and Southeast U.S. with a slight weakness in the ridge over northwest Arkansas. Coverage of showers and thunderstorms have decreased substantially over the Mid-South with the loss of daytime heating. The only remaining showers and thunderstorms are located near Grand Junction, TN. Surface dewpoints still remain high but temperatures have dropped enough to cancel the Excessive Heat Warning early. Short-term models including convective allowing solutions have struggled to resolve convective trends in this weakly sheared environment. The HRRR seems to have a better handle than the other model solutions with the potential for additional showers and thunderstorms overnight if the upstream activity holds together. Confidence in strong to severe thunderstorm potential for the remainder of the night remains low at best as any additional convective activity will likely be elevated. Will make some changes to rain chances for the remainder of the night. Updated grids will be available shortly. CJC && .SYNOPSIS... Issued at 248 PM CDT Thu Jul 4 2024 Hot and humid conditions will prevail for Independence Day. A few strong to severe storms are possible this afternoon and evening. A brief period of mostly dry and cooler conditions will return tomorrow before rain chances ramp up again on Sunday. && .DISCUSSION... (This evening through next Wednesday) Issued at 248 PM CDT Thu Jul 4 2024 Hot and humid conditions encompass the Mid-South as of 2 PM with heat indices ranging from 105-113 degrees. A few stray showers and thunderstorms are depicted on KNQA at this hour due to the surge of moisture ahead of an approaching shortwave. At this time, these storms currently are only threatening heavy rain and frequent lightning. An Excessive Heat Warning for the entire area will continue through 9 PM. A stalled frontal boundary is currently stretched from the Great Lakes to central Missouri. This boundary is pulling moisture ahead of itself and allowing scattered storms to develop in its wake. As this boundary slowly starts moving, a bowing segment will dive SSE across Arkansas and West Tennessee late tonight into tomorrow morning. The bowing segment appears to hit a localized vorticity maxima as it should exit the region by late tomorrow morning. Confidence remains low in severe storm development as shear is on the lower end nearing 30 kts. The lack of shear and mid-level lapse rates near 5 C/km indicate convection would remain surface based (as there is plentiful SBCAPE) and will likely quickly fizzle out once daytime heating ends. Nonetheless, if a strong to severe storm does develop it would most likely be in extreme northeast Arkansas, the Missouri Bootheel, and extreme northwest Tennessee. A cold front will sweep across the region tomorrow evening keeping rain chances around through Saturday morning. Friday may still be a bit humid in some portions of the Mid-South, particularly north Mississippi, until the drier air can prevail. A Heat Advisory may be needed, but given the potential for convection and cloud cover, holding off on issuance for now. Residing behind the front, is a brief period of cooler conditions with highs in the upper 80s and lower 90s beginning on Saturday. Zonal flow will keep conditions dry briefly. Sunday brings the return of rain chances as the possible remnants of Hurricane Beryl interact with a trough. There is a high level of uncertainty with the interaction, so we will continue to monitor for now. DNM && .AVIATION... (06Z TAFS) Issued at 1128 PM CDT Thu Jul 4 2024 Scattered thunderstorms are expected to move across much of the Mid-South overnight and into Friday morning ahead of a cold front. Current radar trends suggest thunderstorms may not be as widespread as 00Z HRRR shows. Decided to use PROB30 instead of TEMPO for all four TAF sites. Along with the thunderstorms, some MVFR ceilings are possible. Behind cold front, VFR conditions will return. Light south winds are expected overnight before shifting to the west as thunderstorms approach. Behind cold front, northwest winds at 5 to 10 knots are expected with light and variable winds Friday evening. && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$ PUBLIC FORECAST...DNM AVIATION...ARS