Area Forecast Discussion
Issued by NWS Memphis, TN
Issued by NWS Memphis, TN
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373 FXUS64 KMEG 252352 AAA AFDMEG Area Forecast Discussion...UPDATED National Weather Service Memphis TN 652 PM CDT Wed Sep 25 2024 ...New AVIATION... .SYNOPSIS... Issued at 140 PM CDT Wed Sep 25 2024 A cold front has passed through the region throughout the past day and has brought our highs into the upper 70s and low 80s. Tomorrow will see similar conditions before the remnants of Helene bring rain and wind on Friday. Rainfall amounts could be up to 3 to 4 inches, especially with northern extent in Tennessee and Arkansas. Lower accumulation of half inch to 1 inch is expected in northern Mississippi. On Friday, highs will be in around 70, gradually increasing into the mid 70s Saturday and Sunday. && .DISCUSSION... (This evening through next Tuesday) Issued at 140 PM CDT Wed Sep 25 2024 Weather is expected to continue to be active across the southeastern CONUS through the rest of the week. A large upper level trough is currently swinging through the Midsouth and will become progressively cutoff through tonight, eventually coming to a standstill over our region. At the same time, this trough will help steer what is now Hurricane Helene into the FL Panhandle tomorrow evening. Helene is expected to quickly move inland and pivot northwestward towards our region on Friday, bringing rain and gusty winds. Impacts from Helene are likely to be mainly from rainfall given high soil moisture left behind by Francine a couple weeks ago. At the moment, 2-3" are generally expected across the region by Saturday evening, with some locally higher amounts possible with northern extent. These factors could potentially aggravate rivers and streams through the weekend. Have opted to hold off on a flood watch but it is anticipated once more consistency in rainfall totals are seen in future guidance. Winds could also provide some concern as recent HRRR/HREF runs have pointed towards an increase in winds along the northern periphery of the merging surface lows across NW TN and NE AR. However, high- end short range ensemble guidance progs winds at 20-25 mph and does not offer enough coverage to warrant any advisories at this time. It should be noted that, with high soil moisture, trees might be more susceptible to being uprooted without meeting advisory criteria. As with any cutoff low, model variance is high earlier on in the forecast cycle than usual. This is only compounded by the interactions that will take place between Helene`s remnants and the cutoff upper low. Current medium/long range ensembles display this uncertainty in the position of the upper low. Some guidance brings it out into the Atlantic by Sunday with others bringing it north and keeping it over the CONUS. However, there is decent confidence with respect to a new shortwave eventually dragging the cutoff low east in to the Atlantic by next Tuesday with an associated cold-frontal passage. Any specific timing or impacts are too far out to be discerned with any accuracy at this time. && .AVIATION... (00Z TAFS) Issued at 650 PM CDT Wed Sep 25 2024 VFR will prevail through the next 24 hours, with winds the primary impact. Kept gusts in for last six hours of the MEM TAF, with NAM time-height progs showing wind speeds increasing to around 20KT just off the deck. MVFR/IFR potential will begin to ramp up after 00Z Friday, with a deepening upper low centered just west of MEM and strong northerly flow at the surface. -SHRA will be possible for the Thursday evening MEM inbounds, with a trend toward MVFR and IFR by 12Z Friday. PWB && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$ PUBLIC FORECAST...JAB AVIATION...PWB