Area Forecast Discussion
Issued by NWS Hastings, NE
Issued by NWS Hastings, NE
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254 FXUS63 KGID 110006 AFDGID Area Forecast Discussion National Weather Service Hastings NE 706 PM CDT Mon Jun 10 2024 ...Aviation Update... .KEY MESSAGES... - Potential remains for a few isolated/scattered thunderstorms to slide east into the area late this evening/tonight. Main chances are west of Highway 281. Storms are not expected to be severe. Lingering isolated activity is possible into Tuesday as a weakening frontal boundary sinks south through the area. - The heat cranks up Wednesday and Thursday. More widespread Heat Index values of mid 90s-near 100 possible on Wednesday, with a smaller area of 100-105 degree values possible on Thursday (mainly along/south of the NE/KS state line). - Better chances for storms return late in the week into the weekend, with the best chances (40-60 percent) currently in the Friday evening-Saturday night time frame. && .DISCUSSION... Issued at 424 PM CDT Mon Jun 10 2024 Currently through Tuesday... It`s been another overall pleasant day across the area, with temperatures this afternoon not too far from normal for this time of year, and outside of some upper level cirrus, skies have been sunny. In the upper levels, the area sits under weak west-northwesterly flow, thanks to a ridge axis extending northeastward through much of the Plains, set up between shortwave troughing moving through the High Plains and larger- scale troughing over the East Coast. At the surface, winds to start the day were light/variable thanks to high pressure over the region...but have turned southerly through the day as that high slides east and low pressure/frontal boundary are shifting through the High Plains. Across roughly the western half of the forecast area, sitting under a bit tighter pressure gradient, gusts at times have reach the 20-25 MPH range. Hasn`t been any surprises with temps this afternoon, at 3PM sitting in the upper 70s to low 80s...with dewpoints still in the 40s-low 50s keeping humidity down. As expected, thunderstorms have fired off to our west along the surface frontal boundary as that upper level trough axis has moved in...and this activity is the main forecast concern as we get into tonight and Tuesday. Overall, there hasn`t been any notable changes to the forecast. Models continue to show a weakening trend in activity as it gets shifts east, with the better upper level and low- level jet forcing, along with instability, remaining north and/or west of the forecast area. Because there still is some uncertainty with the coverage of activity as it slides east, kept precipitation chances in the 40-50 percent range in far WNW areas, dropping off pretty quickly to 20 percent chances further SE. This activity is not expected to be severe. As we get into Tuesday, have 20 percent chances lingering through the day. These chances will be tied to the surface frontal boundary gradually sinking south through the forecast area, with models showing it weakening/becoming more diffuse as the day passes as it continues to lose any upper level push. Expect any activity to be fairly isolated/scattered in nature, a few models show things being quiet after mid-late morning, so there is some uncertainties with timing. Outside of lingering precip chances, the main impact from this front is ushering in light/variable to more NNErly winds to portions of the area. Temperatures aren`t affected, as highs are expected to climb into the mid-upper 80s. Wednesday and Thursday/Thu Night... The first noticeable days of heat of the year are expected to arrive area-wide Wednesday and Thursday. Models showing upper level ridging trying to build its way back north through the Plains, but various disturbances around keep it from getting too strong. The forecast for Wednesday on through the daytime on Thursday is currently dry. Because the ridging is not overly strong, there will be the potential for a disturbance to get in close proximity late in the day Wed-Wed evening...but along with the lower level air mass warming, so does the mid-levels, which increases capping across the area. Most models keep better precipitation chances just off to our NNE. At the surface, potential is there for breezy southerly winds on Wednesday, with that upper level wave to our north looking to push a frontal boundary south into the area Thu/Thu evening...which will be the focus of better thunderstorm chances, continuing on into the overnight hours. Depending how things trend, activity along that boundary could have the potential to be strong/severe. As far as the heat goes, current forecast has Wednesday with more widespread hot temperatures, then Thursday having the potential to be a touch hotter...but focused over a smaller area. Wednesday sits under increased southerly flow and widespread 850mb temps increasing into the mid-20C range...with afternoon high temps in the mid-upper 90s, and with current forecast dewpoints resulting in Heat Index values near 100 in a handful of spots scattered across the forecast area. On Thursday, areas north of that frontal boundary have more northerly winds and cooler temps, but locations near/ahead of that front (areas near/south of the state line) could have highs right at/just above 100, and Heat Index values potentially in the 100-105 degree range. Friday on through the weekend... Periodic thunderstorm chances continue in the forecast Friday on into Monday, with the overall best chances still focused in the late day Friday through Friday night time frame (40-60 percent)...but decent chances (30-50 percent) are also present into Saturday. Models showing the upper level ridge axis sliding east of the forecast area, with the potential for a stronger upper level disturbance to move into the area...this time from the Desert SW as opposed to previous ones being the NWrly flow/ridge-runner variety. Plenty of details to iron out with the timing of this system, with both the onset and just how quickly it pushes through...as that ridge axis keeps its progress on the slower side. Hard to have a lot of confidence in the details, but the Friday evening-Saturday night is the best chances for precip through this entire 7-day forecast period. The lower confidence extends into temperatures for this time- frame, which currently sit in the 80s/90s, but precipitation could throw some wrenches in that. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 705 PM CDT Mon Jun 10 2024 For KGRI/KEAR Airports: - General overview: This is a high-confidence forecast regarding VFR ceiling/visibility, with any potential ceiling expected to be near-to-above 10K ft. (primarily overnight). Precipitation-wise, the vast majority of the period will surely be dry, but a passing shower/weak thunderstorm cannot be ruled out late tonight-early Tues AM. Assuming no convective outflow comes into play, winds will not be much of an issue, with sustained speeds mainly at-or-below 10KT once any residual afternoon gustiness wears off this evening. - Shower/thunderstorm details: Have maintained the previously-introduced mention of generic "vicinity shower" (VCSH), but tweaked the time frame to 07-13Z. At any point during that window, a passing shower/weak thunderstorm is not out of the question, but felt confidence in thunder occurrence was not quite high enough to justify formal TS mention. - Wind details: Assuming any of the possible/aforementioned convection during the 07-13Z time frame does not throw out any "sneaky" outflow/gustiness, winds should not be much of an issue. Right out of the gate this evening, there could be a few more hours of southerly gusts 15+KT. However, by/beyond sunset sustained speeds should average at-or-below 10KT, with direction trending a bit more southwesterly late in the night. During the latter half of the period Tuesday daytime, a weak front will settle into the area, turning direction more northerly for a time but also bringing some uncertainty in "exact" wind direction especially during the afternoon. As a result, for now have just indicated a basic light/variable group (VRB06KT) late in the period, as no matter direction, speeds should be fairly light. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ DISCUSSION...Pfannkuch AVIATION...ADP