Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/28/22

Area Forecast Discussion
National Weather Service Indianapolis IN
1005 PM EDT Tue Sep 27 2022 .Forecast Update... Issued at 1005 PM EDT Tue Sep 27 2022 No major updates to the forecast this evening. Some minor changes to reflect cloud cover and resulting temperature impacts. Clouds have largely dissipated over the region after sunset, and widespread stratocumulus remains well to our north. Guidance continues to bring this area of clouds southward into central Indiana. Trimmed back cloud cover before 04Z based on recent satellite obs. Nudged temperatures down a bit to reflect a few more hours of clear skies and relatively light winds. Increased winds and temps slightly underneath the advancing cloud layer beyond 04Z. Otherwise, forecast remains on track and another chilly night is in store. && .Short Term...(This evening through Wednesday) Issued at 251 PM EDT Tue Sep 27 2022 * Seasonably cool temperatures through the week * Breezy conditions this afternoon diminish after sunset A deep upper level trough will continue to slowly make eastward progress across the region tonight through Wednesday morning, with at least one embedded shortwave noted in satellite imagery. At the surface, high pressure will continue to build into the region from the north while a broad surface low over southern Canada continues to pull away. ACARS soundings depict a fairly deep, well-mixed boundary layer this afternoon along with convective temperatures being reached resulting in blustery conditions across Central Indiana. 17z Observations show gusts have reached up to 25kts at many sites so far this afternoon. Gusty conditions should continue through around sunset when mixing wanes. Due to a tight pressure gradient from the departing surface low and incoming high, winds may remain slightly elevated overnight around 3 to 7 kts regionwide. A similar diurnal wind trend is expected Wednesday afternoon as the pattern remains very similar to today. With high pressure sinking southward, the pressure gradient will slightly weaker tomorrow and winds should be out of the northeast instead of northwest. Still expect gusts of 15 to 20kts tomorrow afternoon as forecast soundings show a mixed layer up to 6kft allowing stronger gusts to mix to the surface. As flow veers and become northerly overnight, expect a fetch of moisture off of Lake Michigan to enhance cloud cover locally. Current satellite imagery shows a fetch of clouds extending from NW to SE coming off of Lake Michigan into northern Indiana. Latest runs of the RAP and HREF show this band becoming more N to S oriented and making its way through Central Indiana overnight. Also, with temperatures falling near dew points overnight, this band of clouds may expand and contribute to areas of lower stratus clouds forming. Expect clouds to break up and rise after sunrise tomorrow becoming a scattered cu deck by Wednesday afternoon as the boundary layer warms inducing mixing. Temperature forecast tonight largely depends on how widespread cloud cover is from the fetch coming off of Lake Michigan. A few sites this past morning dipped just below 40 for the first time this season. Conditions Wednesday morning however may not be optimal for radiational cooling with increased clouds and elevated winds overnight. Therefore keeping morning low temperatures almost the same as last night. The only area of concern for temperatures dropping below 40 is the SW portion of the area from Bloomington to Bedford to Vincennes where winds may be lower and cloud cover should be less. Not concerned with frost as the lowest temperatures in any sheltered area or valley will be around 37 to 38 degrees, and even then temperatures that low will not be widespread. && .Long Term...(Wednesday night through Tuesday) Issued at 251 PM EDT Tue Sep 27 2022 * Cool and dry through Friday. * Chance for tropical remnants to impact portions of the area early in the weekend. The beginning of the long term will be dictated by an amplified ridge over the Midwest. This ridge will tap into cool Canadian Plains air, and transplant it into the Ohio Valley through moderate NW flow. By Thursday, relatively high pressure will encompass the Ohio Valley through CAA enduced mid level height rises. This should, creat broad subsidence over the region clearing skies. The pattern will be fairly progressive though with central Indiana in the upstream portion of the ridge this weekend. Temperatures will be in the mid 60s Thursday, gradually increasing into the upper 60s and low 70s Friday. The main forecast problem for the early portion of the long term will be the possibility of frost Wednesday night. High pressure and the bulk of the cold air mass should lead to the coldest temperatures of the week. The clear skies and light winds will allow the near surface layer to decouple, dropping surface temperatures near the dew point. Current expectation are for lows in the mid to upper 30s, with a few SW locations staying above 40. More uncertainty is added for the weekend forecast with the possibility of tropical remnants from Hurricane Ian. As of this issuance, rain is still not in the forecast for Saturday and slight chances have been included for SE central IN Sunday. However this could change depending on Ian`s track into the CONUS. A few ensemble members have the parent upper level low tracking near central Indiana, of which would significantly increase cloud cover and introduce the possibility of rain, but with the upper level ridge axis expected just east of central Indiana, this should limit north/westward progression. The remnants could also have a large influence on high temperatures this weekend; current expectations are for highs in the low to mid 70s. && .Aviation...(00Z TAF Issuance) Issued at 746 PM EDT Tue Sep 27 2022 Impacts: * Brief periods of MVFR ceilings possible overnight into the morning hours. Discussion: Gusty winds out of the west-northwest, with gusts around 25 kts, will continue to diminish this evening. A light breeze around 5 to 10 kts is expected to persist overnight, given a weakening but still tight pressure gradient across Indiana. Surface high pressure will traverse the Great Lakes from west to east, turning our winds more northerly as it passes by. This northerly flow may allow an extensive stratocumulus deck to our north to move southward. Ceilings should be mainly within VFR levels but could briefly dip to MVFR. A few sprinkles may occur near LAF, though chances are too low to include in the TAF. Breezy conditions could return after sunrise on Wednesday, but not as strong as they were today due to the approaching surface high. Peak gusts may reach 15 to 20 kts during the afternoon. && .IND WATCHES/WARNINGS/ADVISORIES...None. && $$ Update...Eckhoff Short Term...CM Long Term...Updike Aviation...Eckhoff
National Weather Service Charleston WV
935 PM EDT Tue Sep 27 2022 .SYNOPSIS... Winds slacking off tonight as high pressure builds in. Cloudy on Wednesday. Dry weather then persists through the end of the work week. Unsettled weather this weekend with Ian. && .NEAR TERM /THROUGH WEDNESDAY NIGHT/... As of 930 PM Tuesday... Made some amendments to the sky and PoPs grids to account for cloud cover that can be seen on current satellite obs. Have some upslope showers with isolated pockets of thunder in our northern forecast area. These are moving east out of our CWA but they are persisting. Only a few convective models picked up on this (i.e HRRR and NAM-Nest) but they did not have the right coverage. Heavy grid manipulation was needed. As of 210 PM Tuesday... A few showers and thunderstorms are expected to develop across southeastern Ohio and northern West Virginia this afternoon and evening as a strong short wave rounds the base of an upper level low spinning just to the north of the area. A surface ridge builds from the west overnight behind the exiting weak front. Patchy valley fog will develop toward morning as the air mass stabilizes. A persistent weather pattern is expected on Wednesday as the upper low remains just north, with afternoon showers confined along southeastern Ohio and northern West Virginia. && .SHORT TERM /THURSDAY THROUGH WEDNESDAY NIGHT/... As of 220 PM Tuesday... Little change to previous forecast. High pressure with northwesterly flow will continue on Thursday, with dry and cool conditions. Could be some patchy fog in deeper mountain valleys Thursday mornings, but most locations should be fog free. Clouds will gradually increase across the area late Thursday night into Friday with the approach of Ian. && .LONG TERM /THURSDAY THROUGH TUESDAY/... As of 1207 PM Tuesday... High pressure with dry conditions will continue on Friday into the first part of Saturday, when moisture from the remnants of Ian will make its way northward. Overall path of Ian still remains uncertain this weekend, but is generally expected to move into the southeast U.S. by late Friday, before moving westward/northward towards the Appalachians over the weekend. Axis of heaviest rainfall looks to remain to the east of our CWA at this time, and current thinking is we should escape significant hydro impacts. Of course, forecast still remains uncertain at this time period. In addition to rain, gusty winds will accompany remnants of Ian, and ridge tops will be most prone to higher gusts. Low should move off to the east on Monday, with drier weather gradually taking hold. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... As of 830 PM Tuesday... High pressure moves in behind a trough. Winds will start to relax after ~03Z this evening. Currently seeing area wide scattered cloud cover that will continue to move through this evening. Showers and isolated thunderstorms are impacting the northern forecast area from PKB to EKN. Only expecting these to continue for the next hour or two before dissipating giving way to higher ceilings with passing high deck clouds. IFR and MVFR are possible in some heavier showers. Conditions tonight will be VFR but expecting IFR fog tonight at CRW, EKN, HTS, and PKB. MVFR fog for CKB tonight. Fog should dissipate around ~13Z. There is some uncertainty on where the fog will set up and when this MVFR deck will form on Wednesday. Cloud cover tomorrow will be extensive. Most sites, especially the mountain sites, will be under an MVFR cloud deck starting Wednesday afternoon through the evening into the next TAF period. Winds will be out of the WNW shifting to NNE Wednesday evening. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z THURSDAY... FORECAST CONFIDENCE: Low. ALTERNATE SCENARIOS: Timing and location of fog and showers may vary from forecast. MVFR cloud deck timing and location may vary from forecast. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE WED 09/28/22 UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11 EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 CRW CONSISTENCY H H H H H H H H H L M L HTS CONSISTENCY H H H H H H H H H H H L BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY M M M M M M L L L L L L PKB CONSISTENCY H H H H H H H H M M L L CKB CONSISTENCY H H H H H M M M M M M M AFTER 00Z THURSDAY... IFR conditions possible in fog Friday morning. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...FK/JP NEAR TERM...FK/LTC SHORT TERM...JP LONG TERM...JP AVIATION...LTC