Area Forecast Discussion
Issued by NWS Omaha/Valley, NE
Issued by NWS Omaha/Valley, NE
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766 FXUS63 KOAX 091708 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 1208 PM CDT Thu May 9 2024 .KEY MESSAGES... - Scattered showers and isolated thunderstorms are expected across the region today bringing a 20 to 40 percent chance of rain at any given location. No severe weather is expected. - Several rounds of showers and thunderstorms are forecast Sunday through Wednesday. Current indications for the greatest precipitation chances of 50-60%, are expected Sunday night and Monday afternoon. No severe weather is expected. - Slightly above normal high temperatures in the middle 70s to lower 80s this weekend, and again the middle of next week. && .DISCUSSION... Issued at 340 AM CDT Thu May 9 2024 Today and Tonight... An elongated upper level trough extends from essentially from the North Atlantic to the western U.S. The western U.S. anchoring upper level low disconnects during the day today, leaving a closed upper low over the intermountain region of the West. The forecast area will remain under the influence of the cyclonic shear side of the trough today through late evening. Convergent moist, isentropic flow will persist At the surface a surface trough will move southward across the area. The combined effect will be scattered (10-30% coverage) showers. Diabatic effects will allow for isolated thunderstorms during the late afternoon and early evening. Precipitation totals of only a few hundredths, with isolated amounts of one or two tenths where thunderstorms occur, are expected. Temperatures today will be slightly cooler (60s) due to low level cold advection and evaporative cooling. Overnight temperatures generally will be in the 40s. Friday and Saturday... Generally dry conditions are expected, though a shortwave dropping southward from Manitoba/Ontario into the Ohio Valley Friday afternoon may bring portions of western Iowa and extreme eastern Nebraska isolated showers and thunderstorms. Most areas will remain dry. West to northwest winds 15 to 20 mph will gusts 20 to perhaps 30 mph on Friday. A nice day is expected for Saturday with sunshine, light winds and temperatures in the upper 70s. Saturday Night through Wednesday... The closed low over the intermountain region moves slowly east southeast across the central and southern plains. Sharpening the wind field. Large scale isentropic ascent ahead of the system will draw moisture northward from southern Texas across the southern High Plains with models indicating saturation H8-H7 by Saturday night. The attendant surface system will be Oklahoma and Texas, with an inverted trough extending into the northern plains. As forcing mainly will be from the mid-levels, expect any storms that develop to be elevated. The better shear and instability will reside across the southern plains, thus expect only general thunderstorms. The wave moves into the southeast U.S. by Tuesday, but is followed quickly by another shortwave diving southeast across the plains Tuesday night into Wednesday. Mass field response appears limited, as low level moisture return appears questionable. Though cooling mid-levels appear enough to decrease lapse rates. As such, better chances for stronger storms by Wednesday. High temperatures will remain above normal through the period, with highs near 80 by Tuesday. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 1202 PM CDT Thu May 9 2024 VFR conditions are expected to prevail through the forecast period. The exception is in the vicinity of any showers that develop this afternoon when ceilings could briefly lower to Fl020-030. Based on current radar observations, -SHRA will become increasingly possible at KOFK within the next hour. At KOMA and KLNK, confidence in precipitation occurrence at the terminal locations is too low to include in the forecast. Otherwise, north-northwest winds will increase to 12-13 kt with gusts of 18-20 kt. The winds will diminish by 00z-01z. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...Fortin AVIATION...Mead