Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/02/24


Area Forecast Discussion
National Weather Service Cleveland OH
930 PM EDT Fri Nov 1 2024 .SYNOPSIS... High pressure will build in tonight and remain overhead through Sunday morning. High pressure exits east on Sunday, allowing a warm front to lift north across the area Sunday night. The next cold front approaches towards the middle of next week. && .NEAR TERM /THROUGH SATURDAY NIGHT/... Lake effect clouds will continue to gradually clear in NW Ohio while remaining across much of Northeast Ohio and Northwest Pennsylvania into Saturday. Temperatures have been slow to cool so far but will fall quickly after clearing with high pressure building in from the west with light winds. Only real change overnight was to remove the mention of patchy fog as this seems unlikely to be a concern with the drying airmass. Previous discussion...A very quiet first half of the weekend is in store as Canadian high pressure builds in. Stratus off the lake will persist tonight and into a good portion of Saturday across Northeast OH and Northwest PA. There have been some very light radar returns across far Northeast OH and Northwest PA this afternoon, with Ashtabula County Airport reporting a bit of light rain at times. These very light lake effect rain showers will be most prevalent through early this evening as a weak trough axis drops southeast off the lake. Have some minimal (20%) shower chances persisting tonight across parts of far Northeast OH and Northwest PA, with high pressure expected to build in enough by pre-dawn Saturday to end any lake effect rain showers. Lake effect clouds will finally break completely later Saturday afternoon or evening. Locations farther west should see skies go mostly clear this evening and remain mostly clear/sunny through the rest of the near term. Winds will go light and variable tonight as high pressure builds in. Certainly quite the airmass change from the record or near-record warmth the last few days, with temperatures close to seasonal averages through the near term. Lows tonight will range from the low to mid 30s in Northwest OH where skies will clear to the upper 30s and lower 40s where lake effect clouds persist. Highs on Saturday will range from the low to mid 50s in Northeast OH and Northwest PA to the upper 50s to near 60 in Northwest and Central OH. Lows Saturday night will generally be in the 30s, with a few upper 20s likely in colder pockets of far Northeast OH and Northwest PA. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... Going to get into a relatively familiar pattern in the short term. High pressure drifts into New England and low pressure develops in the central plains region. Flow aloft now southwesterly with an upper level ridge to the southeast, and all of this sets up for another period of warmth characterized by increasing southwesterly winds in a tightening pressure gradient in the warm sector ahead of a baroclinic zone. Upper 50s to mid 60s Sunday become mid 60s to mid 70s Monday as 850mb temperatures climb back into the teens. While the cold front will be a long term forecast period event, waves in the aforementioned southwest flow aloft bring the next chances for rain to the CWA. Another scenario where thunder is being left out of the forecast for now, but gusty shower potential returns. Might see some fluctuations in the POPs with these upper level disturbances moving through, and timing/coverage differences should be expected in upcoming forecasts. Could see developing wind issues once again. && .LONG TERM /TUESDAY THROUGH FRIDAY/... Long term begins with eyes on the upper level flow continuing, which is where the best chances for convection will exist prior to the cold front arrival. Have POPs on the gradual increase as a result, and first cold front will arrive late Tuesday night into early Wednesday. Also likely to see a secondary cold front reinforcing the colder airmass towards the end of the week which could generate some precipitation coming off the lake in onshore flow. Like the short term, wind issues prior to and after frontal passage could develop. && .AVIATION /00Z Saturday THROUGH Wednesday/... Broken to overcast skies are in place at all terminals at 00Z with a clearing trend developing in southern lower Michigan which will tend to work into NW Ohio terminals between 02-04Z. Ceilings have ranged from 2800-3500 feet with most locations on the VFR side. Clearing will be slower overnight from North Central Ohio into Northwest Pennsylvania where northwest flow will maintain a shallow lake effect cloud deck. RAP guidance shows low level RH at 925mb increasing overnight which is possible as high pressure expands and inversion heights lower into Saturday. Due to this have clouds trending lower into the MVFR range overnight into Saturday morning. Skies are expected to scatter out in the 15-19Z window on Saturday. Northwest winds will generally decrease overnight to 5 knots or less. The exception is at ERI where flow may remain in the 5-10 knot range off Lake Erie. A land breeze is forecast to try to develop at CLE so winds may back to southwesterly for a period of time overnight. Otherwise, winds will tend to be northerly to easterly on Saturday. Outlook...Non-VFR possible with scattered rain showers Sunday through Tuesday. && .MARINE... Northwesterly winds, easing through tonight and Saturday with wave heights eventually falling below 2ft become east southeasterly 10- 15kts Sunday where open water wave heights return to 1-3ft while protected nearshore zones will be under 2ft. Winds then become offshore 15-30kts Monday and beyond, similar to events from this past work week, ahead of an approaching and strengthening low pressure system. Wave heights will increase rapidly away from shore through Tuesday night with rough conditions expected in the open waters. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...Small Craft Advisory until 11 PM EDT this evening for LEZ149. && $$ SYNOPSIS...Sullivan NEAR TERM...KEC/Sullivan SHORT TERM...26 LONG TERM...26 AVIATION...KEC MARINE...26
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
807 PM EDT Fri Nov 1 2024 .SYNOPSIS... Cool high pressure moves from the Great Lakes eastward going off the New England coast by Monday. This high pressure keeps temperatures across our region closer to normal for this time of year through early next week. A warmer southerly flow of air develops around mid week bringing well above normal temperatures back to our area. && .NEAR TERM /THROUGH SATURDAY/... Key Messages... 2) Light Rain Showers Will Redevelop Overnight into Saturday Morning, Mainly over the western Piedmont 3) Patchy to Locally Dense Fog Returns to the Mountain Valleys Overnight into Daybreak Saturday As of 751 PM EDT Friday: A weak cold front just east of the mtns will continue to move slowly eastward across the forecast area overnight. Satellite imagery continues to show extensive cloudiness along the boundary, so sky cover was bumped up again. Radar looks fairly quiet, so it would appear the shower activity has diminished as expected. The last few runs of the HRRR continue to show redevelopment along the front early Saturday, mainly over the western Piedmont zones, so we re-introduce a slight chance before daybreak. Amounts will be minimal. As for the mtns, the usual valley fog might be hindered by the lingering cloud cover. Otherwise, the cold front should slip south of the forecast area early on Saturday, but clouds will linger across the region. It might take until well into the afternoon before we see much sun. Highs on Saturday will be slightly cooler behind the front, thanks to flow turning northeasterly, but will still end up about 4-8 degrees above climo. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... As of midday Fri: Fairly strong, high pressure will drift across the northeastern CONUS Saturday night and Sunday. Cold front will ooze south of the area; based on reduced thicknesses alone this should result in temps being a few degrees cooler on Sunday compared to the previous day. Although the synoptic setup is reminiscent of CAD over the weekend, this high is a few mb too weak to support classical CAD. Furthermore, 925-850mb winds should veer to northerly over portions of NC/SC in the wake of the front, but continue to appear light (15 kt or less). This will limit the degree of airmass change. Low-level ridge is shown to remain centered near the Southeast coast, and some model solutions maintain southerly flow over the front within the CWA Saturday night, particularly the western areas. With time southerly flow is increasingly likely to occur within that layer, and moistening generally occurs as a result. This warrants some cloud cover lingering Saturday night, diminishing diurnally Sunday, and then redeveloping Sunday night and lasting most of Monday. The deterministic models develop very little to no QPF until Sunday night or Monday, but even then their response is small and limited to the southeasterly upslope areas (below the Blue Ridge Escarpment) and the Savannah River Valley. If precip does develop, it could promote hybrid CAD, although by then the parent high will have drifted into a somewhat less favorable position. More persistent cloud cover should lead to Monday`s max temps trending still cooler, finally returning to around normal in many spots. The currently small chance of CAD further supports such a trend as cooler solutions are incorporated into model blends; if CAD does transpire temps likely would end up at least a little below normal for the majority of the CWA. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 200 PM Fri: Influence of high pressure to our northeast will diminish at least slightly Monday night as it weakens and moves further offshore; flow in the 925-850mb layer atop it will veer, becoming more southerly than SE`ly Tuesday. Precip chances increase a bit with somewhat better model response developing, with upglide persisting and moisture flux possibly being enhanced as next cold front moves into the MS Valley. The airmass will modify and thicknesses increase a little, so temps are most likely going to be at least slightly warmer, although any warming trend will be muted by abundant cloud cover that day, if not the effect of weak/shallow in-situ CAD developing with precip. The moist southerly flow regime will continue until the front reaches the area, which currently does not look likely to occur until after the end of the period Thursday night, so periodic cloud cover and small PoPs remain in the forecast through then. Temps warm back to around 10 degrees above normal Wed and still warmer Thursday. It is worth pointing out that NHC has an area of interest in the southern Caribbean which has a high probability of developing into a tropical cyclone in the southern Gulf of Mexico late next week. The Canadian GDPS is a fast outlier in bringing this system north and allowing its moisture to be pulled into the frontal zone Thursday, resulting in considerably higher QPF over the CWA at that time. Other models (GFS/EC and their ensembles) do not develop this interaction and keep QPF low-impact thru the end of the period. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... At KCLT and elsewhere: VFR at all terminals through the late evening as a cold front moves slowly across the region. The boundary should keep moisture pooled across the region, particularly on the poleward side, with satellite imagery showing a wide band of ceiling restrictions. The guidance seems to hit this fairly hard with MVFR or worse ceiling restrictions developing around daybreak Saturday at all terminals. The LAMP is quite pessimistic with the possibility of brief IFR/LIFR at most terminals. We will lean in that direction, but conservatively for now. Seems likely that a low cloud ceiling will redevelop with some daytime heating Saturday, most likely MVFR into the early afternoon. The wind should be mostly NE behind the boundary into Saturday afternoon. Outlook: MVFR restrictions may linger through Saturday evening, especially at KAVL. Drier weather and VFR conditions are expected Sunday into Monday as dry high pressure builds back over the terminals. Another weak cold front approaches out of the west Tuesday into Thursday bringing light rain chances, and possibly restrictions, back to the terminals. Mountain valley fog and low stratus may develop each morning. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...DEO NEAR TERM...AR/PM SHORT TERM...Wimberley LONG TERM...Wimberley AVIATION...PM
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
900 PM CDT Fri Nov 1 2024 ...New MESOSCALE UPDATE... .MESOSCALE UPDATE... Issued at 900 PM CDT Fri Nov 1 2024 No noteworthy changes are planned for the near term forecast at this time. The area is currently split between a region of low stratus over northern portions of the area and higher clouds and scattered showers over the southern half. Occasional breaks in these clouds have resulted in brief fog development already in the Meridian area early this evening. Showers have been decreasing in coverage and are expected to continue to do so overnight, remaining limited to mainly southwest MS and northeast LA. With a seasonably humid airmass and wet grounds, any breaks in the clouds overnight will encourage additional fog development. And if this is sustained, fog could be locally dense. It remains somewhat difficult at this stage to pin down where that is most likely to occur. The HRRR which was previously showing little fog has trended toward more development in recent runs, especially in the area where the HREF has showed greatest potential, across eastern and central MS. For now, we will continue with a more generic limited fog threat graphic and adjust or consider an advisory if needed as things evolve overnight. /DL/ && .DISCUSSION... Issued at 317 PM CDT Fri Nov 1 2024 Tonight into Saturday: As the upper-level trough continues to pull northeast away from our region, we`re left with the southeastern CONUS ridge overhead today. A portion of the upper-level energy was trapped beneath the ridge - or at least some convectively driven vorticity - as remains evident on satellite imagery over southeast LA today. Reinforcing cold air north of the front has been slowing the mixing out of low clouds today, but clearing overnight is expected with the loss of daytime heating and drier air easing in. When the rain shower activity winds down overnight and skies begin to clear in patches, temps should cool below today`s dewpoint values and initiate fog development. Guidance is a bit varied in where the best potential is for dense fog, so have broadly included "patchy fog" wording in the weather for the whole area tonight and included a Limited threat for the local hazard graphics. Tomorrow, the arrival of some warmer and drier air should mix out clouds better than today and give us highs more in the lower 80s range. /NF/ Saturday night through next week... The pattern across the CONUS will remain active with an amplified, progressive upper pattern. High pressure will generally be in control through Monday as a stalled front dissipates across the area this weekend with fair, warm conditions expected. Highs likely in the mid 80s for most through the weekend with above normal humidity keeping overnight lows elevated, in the 60s F. Our next chance at rain comes Tuesday into Wednesday when an upper trough digs into the Southern Plains before ejecting into the Mississippi Valley. Associated surface cold front will likely bring a band of showers and potentially thunderstorms, a few of which could be stronger with some gusty winds, through the area during the day Tuesday. This front will likely have some similarities to the front currently stalled across the area, resulting in a modest decrease in temperatures into midweek with highs in the middle 70s F north to mid/lower 80s F south. Temperatures in a similar range will continue through the week as the front will likely fail to bring a substantial cooldown and itself stalls despite its best efforts as the upper ridge remains stout. The lingering front and the period of somewhat lower heights with boundary layer moisture not scoured out will likely allow for clouds and some rain chances through the end of the week. This pattern of light winds, boundary layer moisture, wet ground, and stalled/decaying frontal boundary will also allow for patchy and possibly dense fog to develop each night. The degree of fog potential and areas most favorable will be assessed each day but it is possible that hazardous weather outlook graphics or Dense Fog Advisories could be needed at times this upcoming week. Regarding the tropics... We are down to the last month, now, of Hurricane Season and we do have an area of interest that the National Hurricane Center in Miami, FL has designated as having a high chance (70%) of development into next week. Model guidance as would be expected at this stage has a large spread of outcomes as the system in the western Caribbean lifts north. It does seem likely now that the disturbance will attempt to organize and could end up in the Gulf of Mexico by later next week. While it`s too early to be confident, recent seasonal cooling of Gulf water and expected frontal activity near our area make the potential for a higher end hurricane impact local to the ArkLaMiss low at this time. That said, the system has some potential to bring local impacts of some kind in the D7-10 time frame and we will be watching closely with numerous updates on the progress of the disturbance in coming days. /86/ && .AVIATION... (00Z TAFS) Issued at 624 PM CDT Fri Nov 1 2024 An MVFR stratus deck encompasses areas mainly north of a HEZ to JAN to GTR line early this evening with scattered mainly light SHRA persisting across parts of south MS and central LA. SHRA will begin to decrease overnight, though a few areas of -RA will remain possible. However, fog development is expected tonight through Saturday morning resulting in MVFR visibilities, though localized LIFR to IFR is possible. Improvement is expected by mid to late morning, with VFR conditions expected through the remainder of the TAF period. /DL/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 64 83 63 83 / 30 10 0 10 Meridian 63 82 61 83 / 10 0 0 0 Vicksburg 65 82 61 84 / 30 10 0 10 Hattiesburg 64 86 62 85 / 10 0 0 10 Natchez 66 82 63 83 / 30 10 0 10 Greenville 63 80 62 83 / 10 20 0 0 Greenwood 63 82 63 84 / 10 10 0 0 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ DL/NF/86