Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS63 KOAX 220859 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 359 AM CDT Thu Jun 22 2017 .SHORT TERM...
-- Changed Discussion --
(Today through Saturday) Issued at 330 AM CDT Thu Jun 22 2017 Forecast concerns in the short term will be thunderstorm chances/coverage as the cold front pushes southward through this evening. Thunderstorms have struggled to get going over the forecast area with isolated storm near SUX/SD border where the is a pocket of upper level divergence/theta-e advection/low jet forcing...and over central Nebraska.northern KS. Storms that form weaken as they move into the hot air. Height falls were greatest around 110m ht falls over Manitoba with broad height falls over the central part of the country with the flattening of the h5 pattern. The h7 thermal ridge was over much of the forecast area at 12 to 14 degC and this led to highs in the 90s with 100 the hot spot at Albion. H85 dewpoints were 16-18deg C near the front...however much drier toward FNB. Per the GOES-16 satellite loops/WSR-88D radar...there has been an uptick in the storms across parts of the Northern Plains, with more of a diurnal decrease across the southern Plains. The storms over Kansas have been maintaining themselves as they drift east-southeastward. At 08Z, the cold front was north of FSD and near CDR and the warm front was near southern MN. The more organized storms were across northern Iowa and also post-frontal across parts of SD. The h5 closed low pressure system over Saskatchewan travels east into Ontario through 06Z...with 60 to 80m ht falls making their way into SD/MN as the h5 trough deepens. This will push the cold front southward toward Omaha/Lincoln by 00Z and northwest MO by 06Z. We are starting out quite mild in the 70s and 80s with the brisk south winds. High clouds could affect temperatures ahead of the front, however they should warm into the 90s, with readings in the 80s behind the front. As the trough builds in...there is cooling aloft and isentropic lift saturating areas to the north with the chance for thunderstorms. There is a shortwave pushing across the forecast area this morning with upper level support and something isolated could develop...however, the most recent cams/nam12/gfs/ec are mainly dry thru 18Z when we start to see increasing chances from 18z-22Z in northeast Nebraska...with chances settling southward 22z-06Z. Will monitor the latest radar and possibly include some pops with the morning convection near KS...otherwise will bring increasing chances along and behind the front. Instability increases ahead of the front today to 2000-3000j/kg, however the 0-3km 35-45kt bulk shear is displaced north of this area. SPC has areas in the vicinity of the front in the marginal risk for severe storms with hail and damaging winds possible. The trends have been for the organized storms to be northeast of the forecast area. Forecast soundings support at least some strong to severe where storms form along with heavy downpours of rain. Reinforcing cold air with a shortwave trough in the northwest flow could spark some showers, however for now with the mid level moisture just included instability cu. Highs Friday are forecast to be in the 70s Another deeper area of low pressure rotates through the flow across MN Saturday and this cold core system could have some showers and thunderstorms with it, however it should remain to the north of the forecast area. Highs again for Saturday are expected to be in the 70s with morning lows in the 50s. .LONG TERM...(Saturday night through Wednesday) Issued at 330 AM CDT Thu Jun 22 2017 The extended forecast still has the high pressure aloft anchored over the desert southwest. The northwest flow aloft and cooler highs in the 70s Sunday and Monday moderate for Tuesday and Wednesday with highs in the 80s. There are a few chances for showers/storms and although the medium-range models have timing differences, we have included scattered thunderstorms Wednesday/Wednesday night.
-- End Changed Discussion --
&& .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1143 PM CDT Wed Jun 21 2017 VFR conditions are indicated through the TAF cycle. Shower/storm threat tonight has not materialized, so should see a few high- level clouds and winds decreasing, along with increasing wind shear. Mid-level clouds likely will increase for a time on Thursday around frontal passage, but confidence in showers/storms is too low to include yet. Wind shift will arrive in the 22-00Z time frame. Speeds in the afternoon both before and after the wind shift will be around 10-15kt. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...Zapotocny LONG TERM...Zapotocny AVIATION...Mayes is the U.S. government's official web portal to all federal, state and local government web resources and services.