Area Forecast Discussion
Issued by NWS Hastings, NE
Issued by NWS Hastings, NE
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650 FXUS63 KGID 021706 AFDGID Area Forecast Discussion National Weather Service Hastings NE 1206 PM CDT Tue Jul 2 2024 .KEY MESSAGES... - Another upper level disturbance and surface frontal boundary are expected slide through the area today into this evening, bringing additional thunderstorm chances. While much of the forecast area will have the potential for strong to marginally severe storms, mainly this afternoon/evening, the overall best chances look to be along/south of a line from Geneva to Phillipsburg. - Wednesday evening and overnight will bring another chance for strong to severe storms to the area, with the best chances being mainly along/west of HWY 183. - Storm chances linger into the morning/early afternoon hours on Thursday/Independence Day, but the forecast dries out for the evening/fireworks time. - Dry forecast continues on into Friday/Friday night, with periodic storm chances returning this weekend into early next week. Overall confidence in the timing/location of those chances isn`t the highest at this point. && .DISCUSSION... Issued at 423 AM CDT Tue Jul 2 2024 Currently on into tonight... Upper air and satellite data show the area continuing to sit under southwesterly flow early this morning, set up between broader troughing extending south-southwest out of central Canada and ridging extending northeastward from the TX/OK/LA/AR border area. An embedded shortwave disturbance and a surface warm frontal boundary sparked off thunderstorm activity late Monday afternoon...and while the coverage/intensity has diminished during the overnight hours, a swath of scattered showers and weak storms continues early this morning. Lift along the convergence zone of a 40-50+ kt low level jet is aiding in keeping this activity going, which is and looks to remain mainly south of I-80 the rest of this morning. At the surface, the forecast area sits in a weaker regime, north of the more pronounced warm/stationary front running through central into northeast KS...resulting in light/variable winds for the majority of locations. Satellite imagery also showing most of the central/southern portions of the forecast area under mostly cloudy skies with mid-upper level cloud cover...with the northwest third or so with areas of mostly clear skies, but spots of low level stratus sinking south. The opportunity to cool more than other areas with less cloud cover, light winds and recent rains has resulted in some patchy fog...which will remain a concern through the rest of the early morning hours. Spots with visibilities under one mile will be possible. Looking to the rest of today into this evening, the main concern remains with thunderstorm chances. Models showing another upper level shortwave disturbance will be making its way east out of the Rockies and onto the Plains today...and with lift ramping back up with its arrival, hard to completely rule out preciptiation for any particular place during the 12-00Z time frame today. In general most models show continued weakening of the ongoing activity early this morning...but show the potential for at least scattered activity to pick back up by mid-late morning. Though the current surface pattern is weak across the forecast area currently, models showing with the arrival of that upper level wave, a more organized cool front will start to push southeast through the area...providing another focus for thunderstorm development. Big question is with the progress the front makes through the day. Even with this activity that we had come through last evening through tonight, it wasn`t a system that `cleared out` the area of instability like some systems can...so while any storms that develop esp. this afternoon/early evening will have instability/shear sufficient for strong to at least marginally severe storms to be a concern, locations along/south of that boundary will have more juice to work with. The majority of the forecast area is included in the SPC Day 1 Marginal Risk area, with the Slight/Enhanced areas just to our south...as a decent share of models show the front making enough southward progress to push the greater threat out. But...some models showing it being a closer call whether the front can get out of the forecast area before those stronger storms develop...it`ll be close. Locations roughly along/south of a Geneva-Phillipsburg look to have the better chances of seeing any severe storms with any frontal slow down...something to watch during the day. Outside of precipitation chances, trended highs down a touch with expected partly to at times mostly cloud skies and precip potential...with upper 70s-low 80s for most of our Neb counties, and mid 80s-low 90s near/south of the NE-KS state line, which will be ahead of the front longer into the day. Heat index values near 100 are still possible, mainly across portions of Jewell, Mitchell, and Osborne counties. Later into the evening/overnight, the better precipitation chances push further south into KS...and while did keep a sliver of low chance (20 percent) PoPs in far southern portions of the forecast area, it`s possible the entire area will be dry as we get closer to/after midnight. Wednesday and Thursday/Independence Day... Confidence in Wednesday`s forecast, mainly with preciptiation chances, is not overly high. Expecting generally zonal flow to be in place in the upper levels to start the day...with the potential for some at least scattered activity to work its way into far southern portions of the forecast area, as a weak shortwave disturbance slides east across KS. Have those precipitation chances currently confined to Rooks/Osborne/Mitchell to start the day...some models say that could be expanded a touch north, others say it`ll be dry...so already some questions to start off the day. Precipitation chances remain low throughout the rest of the day (20 percent or less), and focus during the afternoon turns to the High Plains. Expecting winds to start the day on the light/variable side, turning more solidly southerly through the day...as surface low pressure deepens over the High Plains and a more notable frontal boundary develops ahead of an approaching upper level shortwave disturbance. By mid-afternoon, thunderstorms are expected to develop along this boundary, then the question becomes how it evolves as it pushes east into the evening/overnight hours. There are some notable differences between models with just how much activity actually develops out west, and what actually makes it this far east. At this point, NBM/forecast precipitation chances are on the more optimistic side of activity pushing east, and chances are anywhere from 50-80 percent through the Wed night-Thur AM time frame. Roughly the western third of the forecast area is included in the SPC Day 2 Slight Risk area...with the remainder of the area in the Marginal Risk area. While models show sufficient deeper layer shear in place area-wide...the axis of better instability is focused along/outside of the western edge of the forecast area. Hail/damaging winds would be the primary threats. Precipitation chances continue on into the day on Thursday/Independence Day as another, stronger upper level system moves through the Northern/Central Plains. Current models show the best chances coming during the first half of the day, perhaps into the early afternoon...but do have activity clearing the area by mid-late afternoon...with the evening and fireworks activities looking dry. As mentioned above, winds on Wednesday turn back to the south with time, with speeds anywhere from 10-15 MPH in the east to 15-20 MPH in the west. Highs on Wednesday are in the mid-80s area-wide. On Thursday, with that stronger system passing to our north, a surface cool front sinks south through the area, ushering in northwesterly winds, which may be on the breezy side around 15-20 MPH through the afternoon...before diminishing for the evening/overnight hours. Highs on Thursday are forecast to be in the mid 70s-near 80 across most of our Neb counties, with mid-80s across KS. Friday on into early next week... For the end of the week into early next week, between the upper level system that passes to our north on Thursday digging a bit further south with time and high pressure/ridging becoming more established over the western CONUS, our pattern turns to more northwesterly flow. The dry forecast Thursday evening continues on into Friday/Friday night and at least into the first half of the day on Saturday. Another upper level low pressure system looks to slide southeast out Canada into the Dakotas later in the day Saturday into Saturday night, bringing the next precipitation chances. Additional periodic low chances (20 percent) continue on into Sunday and Monday, but confidence in timing/location drops the further out in time we go. As far as temperatures go, Friday is fairly similar to Thursday with mid 70s-mid 80s, with the upcoming weekend highs solidly in the 80s to around 90 in spots. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 1147 AM CDT Tue Jul 2 2024 Low clouds should scatter out mid-day looking at upstream obs. Hit and miss MVFR ceilings are moving through the area, so will have to keep watch and see if a TEMPO will be needed for the next couple of hours. The biggest uncertainty will be FG formation tomorrow morning. Leaning towards patchy right now as SFC winds will have a WSW direction, which is normally a drying wind for the TAF sites. Cirrus aloft may also play a small roll in hindering FG formation tomorrow morning. The winds look to gust into the teens this afternoon before tapering off this evening as a SFC high settles into the area. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ DISCUSSION...ADP AVIATION...Beda