Area Forecast Discussion
Issued by NWS Paducah, KY
Issued by NWS Paducah, KY
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044 FXUS63 KPAH 161118 AFDPAH Area Forecast Discussion National Weather Service Paducah KY 618 AM CDT Thu May 16 2024 .KEY MESSAGES... - Shower and thunderstorm chances will increase this afternoon into tonight. A few strong to severe thunderstorms are possible, with large hail and damaging winds being the primary threats. - Widespread showers and isolated thunderstorms are forecast Friday into Saturday. While a strong to severe storm cannot be ruled out, locally heavy rain and flash flooding will be the primary threats. - Dry and very warm conditions will return Sunday and Monday. The next chance of widespread thunderstorms is forecast Tuesday into Wednesday. && .UPDATE... Issued at 617 AM CDT Thu May 16 2024 Updated Aviation discussion for the 12z TAF issuance. && .DISCUSSION... Issued at 300 AM CDT Thu May 16 2024 Early this morning...Patchy fog has developed across parts of the area, with visibility values of generally 1 to 6 SM being observed. With mid and high cloud cover increasing from the west, the risk of widespread dense fog looks rather low at this time. However, locally dense fog could develop near daybreak, and if this occurs, a Special Weather Statement or even a Dense Fog Advisory may be needed. Today through Saturday...A diffuse warm frontal boundary will lift northward through the region this morning in association with surface low pressure organizing across the southern Great Plains. This will allow high temperatures to warm into the upper 70 to lower 80s over much of the area. As an H5 trough approaches from the west this afternoon, scattered convection will develop over southern and central MO and move eastward into the area. The 16/00z HREF mean develops about 500-1000 J/kg of SBCAPE over the area, along with 30-40 kts of 0-6 km shear. These parameters will be marginally supportive of strong to severe convection, and SPC has maintained a marginal risk with their newest Day 1 Outlook across nearly the entire forecast area. Hodographs look to be fairly straight, so isolated large hail and perhaps a few damaging wind gusts will be the main severe hazards. The convection will decrease in intensity tonight as H5 flow weakens quickly. On Friday, the surface low over the southern Plains will move over the region. This will initiate widespread showers and thunderstorms, with the potential for several rounds of moderate to heavy rain for some areas and associated flash flood potential. See the Hydrology section below for details. SPC has introduced a Day 2 marginal risk for the areas near the AR/TN border, but confidence in any severe potential looks is low due to uncertainty regarding surface-based instability developing. High temperatures Friday will be confined to the lower to middle 70s due to the the clouds and precipitation. By Saturday, the surface low will begin to exit to the east, allowing for a drying trend from west to east during the morning hours. There will be some clearing of skies in the afternoon, allow temperatures to warm into the upper 70s to lower 80s. Sunday through Wednesday...Strong H5 ridging and surface high pressure centered over the Mid and Deep South will allow for high temperatures to climb into the middle to upper 80s beginning Sunday into the first half of next week. A few locations may even climb into the lower 90s. Dew point temperatures will still be fairly tolerable in the lower to middle 60s, but it will certainly be feeling like summertime as we approach the end of May. Precipitation chances look to ramp up Tuesday into to Wednesday, and model guidance has come into better agreement about another fairly deep neutral to negatively-tilted H5 trough ejecting into the central Plains. As it stands, surface low pressure is progged to develop over the southern Plains and move into the Great Lakes, with convection firing ahead and near the associated surface cold front. Given the positioning and antecedent airmass, there could be a severe thunderstorm potential with this system, but given the nearly one week range, confidence in this solution is pretty low...but merits watching. && .AVIATION /12Z TAFS THROUGH 12Z FRIDAY/... Issued at 617 AM CDT Thu May 16 2024 Scattered low stratus and fog restrictions will quickly mix out and dissipate by 13-14z. Afterwards, high clouds will thicken and lower throughout the day, with some FEW-SCT CU decks developing as well. Numerous to widespread showers and thunderstorms will move into the region late tonight, mainly in the 03-09z window, with periods of MVFR vsby restrictions expected in addition to lighting activity at CGI, PAH, and MVN. && .HYDROLOGY... Issued at 300 AM CDT Thu May 16 2024 Recent rounds of heavy rain over the last seven days have resulted in much of the region receiving 100-200% of normal rainfall for this period, with isolated areas seeing up to 300% of normal rainfall. With a prolonged period of dryness stretching back to February, the top 100 cm of soil remains in the 20th to 50th percentile. Nevertheless, streamflows have recovered to near average values (between the 25th and 75th percentile). The incoming system tonight through Saturday morning could bring multiple rounds of locally heavy rain, and potentially some flash flooding. The first round would be from any thunderstorms that develop tonight, followed by widespread showers and pockets of heavy rain associated with the surface low moving through the region Friday into Saturday. Six hour flash flood guidance is about 2.5-3.5 inches over the area. The latest WPC QPF has a broad brush of 1-2 inches for the area, but as we get closer, several CAMs have shown corridors of 2-4+" of QPF, particularly over southeast MO into western KY. The corridor of higher rainfall appears to be in response to a cold-pool boundary developing over the region from the convection forecast for today and tonight. If this feature does materialize, it would act as a focus for training convection with higher rainfall amounts. PWAT values are forecast to be in the 75-90th percentile, so efficient warm rain processes are possible as well. Since we are still 24-36 hours away from the start of the heaviest rain, confidence was still too low for a Flood Watch, but one may be needed with later forecast packages. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ UPDATE...DWS DISCUSSION...DWS AVIATION...DWS HYDROLOGY...DWS