Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/29/20

National Weather Service Albany NY
951 PM EDT Fri Aug 28 2020 .SYNOPSIS... A frontal boundary will lift northward, as a warm front tonight bringing some showers and isolated thunderstorms. The air mass will become more humid with showers and scattered thunderstorms some with heavy rainfall and gusty winds tomorrow ahead a low pressure system and a cold front. A cooler and less humid air mass will settled into the region for the 2nd half of the weekend into early next week with high pressure building in. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Mid and high clouds quickly spreading east and will slow the cooling of temperatures this evening and tonight. Some very isolated showers are brushing the NY/PA border and could affect the eastern Catskills. Some sprinkles and showers could form overhead through the early morning hours as warm advection and moisture advection increases overnight. Between midnight and daybreak many areas could be seeing intermittent showers, maybe even a rumble of thunder in western areas. Some patchy fog is possible as rain increases in coverage. Just some minor adjustments to temperatures, rain timing and sky cover through tonight. Previous AFD has a few more details and is below... A stationary front over the NY-PA border, northern NJ and coastal southern New England will begin to lift northward tonight as a warm front. The mid and upper level flow will become zonal ahead of low pressure system moving into the Great Lakes Region. A weak sfc high north of the warm front will weaken and move down stream. The low-level warm advection, as well as theta-e advection will increase ahead of the warm front tonight. Some weak elevated instability with mean MUCAPE values of less than 500 J/kg is noted on the 00Z HREFS overnight. The Showalter values get into the 0C to -2C range over most of the forecast area between 06Z-12Z on the latest NAM. Sfc dewpts start to creep up and latest 12Z GEFS indicate PWATS start to rise to 1 to 2+ STD DEVs above normal towards daybreak. We kept a slight chance of thunderstorms overnight Clouds will thicken and lower overnight with the increasing thermal advection and we gradually increased POPS into the high chance and likely range. Lows will be in the mid 50s to around 60F north of the Capital Region...and upper 50s to upper 60s from the Capital Region south and east. Some patchy fog may also develop with the showers and isolated thunderstorms. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/... Tomorrow...The air mass becomes very moist and humid as the warm front lift north of the region. Some of leftover moisture from TC Laura may be tapped, but the majority of the remnants should remain south of the region over the northern Mid Atlantic States. PWATS may increase to +2 to +3 STDEVs above normal in the 1.5"-2.0" range with the higher values south and east of the Capital Region. Sfc dewpts increase into the 60s to lower 70s. Cloud cover will likely become an issue for widespread strong to severe thunderstorm development. However, some of the CAMs are indicating that some breaks may be possible towards the afternoon ahead of a prefrontal disturbance and a cold front approaching from the west. Locations from the Capital Region north and west will possibly be located near an axis of better deep shear /0-6 km bulk shear values/ 35-40+ kts and moderate instability with mean SBCAPE values of 1000-1500 J/kg based on the 00Z HREFS. The mid-level lapse rates are very weak /less than 6C/km/ in the tropical like air mass, but pcpn loading into any organized convection may yield some isolated to scattered strong to severe thunderstorms with wet microbursts. If we do not get the sfc heating, then this threat will be limited to nil. Some of the CAMs like the 12Z 3-km NAMnest and the HRRR are showing a line of showers and thunderstorms moving through in the mid to late pm. The Marginal Risk from SPC looks fine at this point. The elevated PWATs above normal in the muggy air mass will allow for some locally heavy rainfall. Poor drainage/urban flooding of low- lying areas and an isolated flash flood will be possible. Some locations still desperately need the rainfall based on the latest drought monitor and DGTALY product where parts of extreme eastern NY, and the southern Adirondacks are in D0 /abnormally dry/ to D1 in western New England /moderate drought/ and spotty severe drought conditions in Litchfield Co. Temps on Saturday will be in the mid 70s to lower 80s in the valleys and upper 60s to mid 70s over the higher terrain. Saturday night...The showers and thunderstorms will end from west to east quickly in the early evening, as the cold front moving through. Cold advection will begin to spread across the region. The mid and upper level trough axis will lag upstream so some isolated to scattered showers are possible especially from the Mohawk Valley/Capital Region/Berkshires northward. Dewpts will be lowering upper 40s to 50s, as the actual lows will get into the 50s to around 60F. Sunday...Brisk and cool conditions, as the upper trough axis moves through some light orographically forced showers are possible over the western Adirondacks and southern Greens as some Lake Ontario moisture is tapped until noontime. Brisk northwest winds of 10 to 20 mph are possible with some gusts 25 to 30 mph. H850 temps fall to about +6C t +10C from northwest to southeast across the forecast area. Partly to mostly sunny skies are expected with temps running a little cooler than normal with comfortable humidity levels. Highs will be in the upper 50s to mid/upper 60s over the hills and mtns, and lower to mid 70s in the valleys with a few upper 70s in the mid Hudson Valley. Sunday night...High pressure builds in with decreasing winds and a cool and pleasant late August night. Lows will be in the 40s to lower 50s with near ideal radiational cooling conditions. It will feel a little bit like early Fall. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Dry and tranquil weather Monday with highs in the 70s but upper 60s higher terrain. A southern stream weak upper impulse drifts north and east out of the TN/OH Valley Tuesday and there are some disagreements in sources of guidance and ensembles with how far north the moisture, clouds and chances of showers spreads. Lots of uncertainty, so including isolated to scattered showers with the best coverage in the mid Hudson Valley and NW CT Tuesday. Highs Tuesday in the 70s with upper 60s higher terrain. Northern stream upper energy builds east through Canada and the Great Lakes Wednesday into Thursday with relatively strong warm advection and low level forcing Wednesday. One upper impulse departs with a potential dry period sometime in the Wednesday night or Thursday time frame. Guidance/ensembles disagree with the timing of the exit of this upper impulse and slight cooldown and drying period. Another upper impulse embedded in the mean upper troughing and cyclonic upper flow in eastern Canada/North America approaches later Thursday into Friday. Again, disagreements in guidance and ensembles exist with the trailing upper energy in the Thursday to Friday time frame. So again, there is lots of uncertainty in the Wednesday through Friday time frame. Therefore, including scattered showers and isolated to scattered thunderstorms. Boundary layer temperatures should be somewhat warm, so surface temperatures will potentially be warm as well, before any cold advection spreads across our region, which may be Thursday, Friday or beyond. Highs Wednesday in the mid 70s to near 80 but lower 70s higher terrain. Highs Thursday around 80 to mid 80s but mid to upper 70s higher terrain. Highs Friday very similar to Thursday, maybe a degree or two cooler than Thursday. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... VFR conditions prevail this evening with mid and high clouds thickening into the early morning hours. A warm front will bring increasing chances for showers to all TAF sites between 06Z-10Z with VCSH being indicated. Between 10Z-16Z VFR ceilings and MVFR visibilities with predominant intermittent showers at all TAF sites but there will be brief periods with no rain. Including PROB30 for MVFR ceilings in any steadier showers with visibilities bordering on IFR. By 15Z-17Z, steadier showers with MVFR ceilings and visibilities and PROB30 for visibilities and ceilings bordering IFR. Basically, one wave of showers around daybreak to mid morning, a possible brief 1-3 hour decrease in coverage, then another wave of steadier showers and isolated thunderstorms in the afternoon. Isolated nature to the thunderstorms suggests not adding to TAF at this time but future TAFs will likely add them once we see storms develop and can track them. Nearly calm winds tonight will become south to southwest Saturday morning at 10 Kt or less and continue through the afternoon. Outlook... Saturday Night: Moderate Operational Impact. Chance of SHRA. Sunday: Low Operational Impact. Breezy. NO SIG WX. Sunday Night: No Operational Impact. NO SIG WX. Monday: No Operational Impact. NO SIG WX. Monday Night: No Operational Impact. NO SIG WX. Tuesday: Moderate Operational Impact. Isolated SHRA. Tuesday Night: Moderate Operational Impact. Scattered SHRA. Wednesday: Moderate Operational Impact. Scattered SHRA...TSRA. && .FIRE WEATHER... A frontal boundary will lift northward, as a warm front tonight bringing some showers and isolated thunderstorms. The air mass will become more humid with showers and scattered thunderstorms some with heavy rainfall and gusty winds tomorrow ahead a low pressure system and a cold front. A cooler and less humid air mass will settled into the region for the 2nd half of the weekend into early next week with high pressure building in. The RH values will increase close to 100 percent tonight and Sunday morning, and then only lower to 60 to 75 percent tomorrow in the humid air mass. The winds will become south to southeast at 5 to 10 mph late tonight, and will be southerly at 5 to 15 mph tomorrow, and shift to west to northwest at 10 to 15 mph tomorrow night. Overall, a widespread soaking rainfall is possible late tonight through tomorrow. && .HYDROLOGY... No widespread problems are expected on the main stem rivers the next several days. More showers and isolated to scattered thunderstorms are expected tonight into tomorrow. High PWAT values will allow for more heavy downpours /briefly intense rainfall rates/ and some isolated flash flooding/urban flooding cannot be ruled out. Most areas will see anywhere from three-quarters of an inch to an inch and a half of rain, but some localized higher totals around 2 inches are possible. The rainfall won`t be heavy enough to cause any issues on the larger rivers. The MMEFS guidance continues to show no flooding on the rivers. Dry weather is then expected for Sunday into Monday which will allow for river and stream flows to recede. Some showers and thunderstorms as we head into the mid week. For details on specific area rivers and lakes, including observed and forecast river stages and lake elevations, please visit the Advanced Hydrologic Prediction Service /AHPS/ graphs on our website. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Wasula NEAR TERM...NAS/Wasula SHORT TERM...Wasula LONG TERM...NAS AVIATION...NAS FIRE WEATHER...Wasula HYDROLOGY...Frugis/Wasula
Area Forecast Discussion
National Weather Service Binghamton NY
811 PM EDT Fri Aug 28 2020 .SYNOPSIS... A few showers and isolated thunderstorms are anticipated as a warm front lifts north mainly in Northeast Pennsylvania this evening, and then across central New York later tonight. A cold front brings more showers and thunderstorms Saturday, a few with gusty winds and locally heavy rain. Generally dry and quiet weather returns Sunday and Monday with cooler temperatures. && .NEAR TERM /THROUGH SATURDAY NIGHT/... 630 pm update... Just minor changes to better represent current conditions. Upped cloud amounts into Saturday. Convection in NEPA isn`t doing much and thunderstorms were short lived. previous discussion... A complex and rather complicated forecast in the near term period. A few showers and perhaps isolated thunderstorms will continue rolling through NE PA into this evening; mainly south of Towanda--Montrose and Honesdale. SPC is still highlighting this area for a marginal threat of a severe storm or two...therefore there is a low chance for some isolated gusty winds or hail. Further north, across all of CNY it should stay mainly dry under partly to mostly cloudy skies this evening. Temperatures will hold in the 70s for most locations. Overnight: A complex forecast as we have the remnants of Laura moving into the Ohio Valley, combining with a rather strong wave of low pressure across the upper Great Lakes. A stationary boundary across central PA and far southern Michigan is progged to lift off to the northeast overnight. This will bring increasing low level moisture and instability. CAMS and other near term guidance is struggling with the various areas of convection out there, and how these will move overnight. Current and best thinking is that the chance for showers and embedded thunderstorms really begins to increase after midnight, as a weak wave moves through and PWATs reach 1.8 inches. Think the RAP may be handling the overnight scenario best, so stuck close to that guidance. The HRRR is a little slower and doesn`t really fill in the shower and t`storm activity over our region until after 3-5 AM. Saturday: There will likely be a round of moderate to occasionally heavy rain with embedded t`storms to begin the day as the pre-frontal trough lifts through. The majority of the remnants of Laura are progged to remain just south of our CWA, but some deeper, tropical like moisture still gets advected northward into our area. PWATS hold between 1.75 and 2.0 inches through at least early afternoon areawide, and warm cloud depths approach 12 k very efficient rain processes are expected. There should be a small break in the showers and perhaps even some break of sun late morning or early afternoon. This may be enough to increase instability for our area. The 12z NAM is showing between 1000-1500 J/kg of MLCAPE, meanwhile the GFS is a bit lower between 700-1200 J/kg. There will be plenty of forcing and deep layer shear around 35-45 kts. SPC currently had much of the area under a marginal risk for severe storms, but would not be surprise to see portions of our FA upgraded in future updates...especially if it becomes more apparent that there will be enough instability present. WPC also has CNY and NE PA under a marginal risk for excessive rainfall and flash- this potential will also need to be watched closely. A strong cold front then pushes through from NW to SE during the late afternoon and evening. This will allow the showers and storms to taper off from NW to SE starting around 3-5 PM across the Finger Lakes, and reaching I-81 in NY by 4-6 PM, and finally clearing NE PA by 6-9 PM. There could even be some late day breaks of sun across the western areas. It will be humid on Saturday with highs in the upper 70s to lower 80s. Mid and upper level trough moves overhead Saturday night, with a rather potent shortwave rotating through across Lake Ontario after midnight. Cooler air aloft will allow for some lake induced instability and enhanced showers in a NW to SE flow...these showers and isolated t`storms could impact the norther portion of our CWA, up toward the NY Thruway corridor overnight. Further south across the Twin Tiers and NE PA is should be mainly dry overnight and a little breezy with lows in the 50s. && .SHORT TERM /SUNDAY THROUGH MONDAY/... 235 PM UPDATE... Northwest flow combined with a large upper low over Quebec may bring a few showers Sunday, mainly along and north of the I-90 corridor and into the Catskills. Showers will be supported early in the day with a surface trough swinging through in the morning hours, High pressure building in during the afternoon should end most of the showers. That same high pressure will slowly slide southeast into western New England by 00Z Tuesday keeping the area dry for the remainder of the short term. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... 235 PM UPDATE... No changes to the long term. Period is fairly quiet as we begin with dry weather. Then, a southwest flow develops and gradually brings moisture slowly increasing the chance for showers each day. By Wednesday, a short wave swinging by will focus the moisture and bring a higher chance for showers and thunderstorms into Thursday. 415 AM Update... The National Blend of Models (NBM) was used as a starting point for the long-term grids. The week starts out dry with high pressure over the Northeast U.S. on Monday. The high gradually to retreat off the New England and Mid- Atlantic coast during the middle of next week. Return flow around the high and ahead of the upstream trough over the central CONUS will lead to a warming trend. The forecast includes an extended period of chance for showers and thunderstorms for midweek but PoPs were generally kept below NBM (20-40 percent) due to uncertainty in the forecast (with several fast-moving disturbances rounding the base of the upstream trough. The best chance for showers and storms will be when the cold front moves through our region. However, timing of the fropa is still uncertain. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... Mainly VFR this evening with ceilings generally at around 5000 to 8000 ft, but a passing warm front will cause ceilings to drop and will also bring in additional chances for showers and mist tonight. Ceilings start dropping back to MVFR and even IFR first at KRME, KITH, KBGM and KELM after 6Z, followed by KAVP and then KSYR around and just after sunrise. Chances for showers and some rumbles of thunder will be ongoing into the daytime hours as ceilings start to slowly lift to MVFR and low VFR. However, thunderstorms become likely from around 16Z to 20Z as a cold front moves through. Towards the end of the forecast period, clouds begin to scatter out with a return to VFR into the evening. Winds turning to the southwest come in at around 5 to 10 kts tonight, but increasing winds aloft will bring in a chance for some low level wind shear especially at KRME tonight. For Saturday, winds increase to around 10 to 15 kts with higher gusts before winds start to turn calmer into the evening. Outlook... Saturday night...Restrictions possible in lingering showers, otherwise mainly VFR. Sunday through Monday night...Mainly VFR, but valley fog likely Sunday night for at least KELM and possibly other terminals. Tuesday...Restrictions possible with a chance for showers. Wednesday...Possible restriction with a chance of showers and thunderstorms. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && $$ SYNOPSIS...MDP/TAC NEAR TERM...MJM/TAC SHORT TERM...DGM LONG TERM...DGM/JRK AVIATION...HLC
Area Forecast Discussion
National Weather Service State College PA
1125 PM EDT Fri Aug 28 2020 .SYNOPSIS... Rounds of showers and thunderstorms will continue through the first part of the weekend, before conditions dry out Saturday night and Sunday. Additional rainfall is likely at times early next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Anomalous southwesterly low level jet and plume of tropical moisture will overrun old outflow boundary south of Pa overnight, bringing additional showers to the region. Evening SPC mesoanalysis indicates only minimal capes across the region. However, expect increasing instability late tonight, as southwest flow increases ahead of approaching upper trough. The instability, combined with increasing large scale forcing ahead of upper trough, could lead to some late night tstorms with heavy downpours. Latest HRRR supports the possibility of spot amounts of around 1 inches overnight. Given the recent dryness, believe the threat of flooding is quite low. High humidity and a southwest breeze will hold temperatures up tonight, with mornings lows likely ranging from the mid 60s over the northwest mountains, to the low 70s across the Lower Susq Valley. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... A large scale upper trough is forecast to move eastward across the Northeast and push a cold front across the Appalachians on Saturday. Tropical moisture associated with the remnants of Laura will be drawn north ahead of the approaching trough, bringing a fairly widespread rain with embedded thunder over the eastern half of the forecast area early Saturday. Model soundings support breaking clouds by afternoon, as low level jet and plume of tropical moisture shifts east of the state. Trailing cold front is then progged to sweep southeast across the region during the afternoon and early evening, accompanied by a last round of showers or thunderstorm in some spots. A few of the storms could be strong to severe, with the greatest risk across the extreme southeast Pa per latest SPC guidance. Deep-layer shear should be sufficient ~30kts for some organization, but modest instability due to early day cloud cover suggests a marginal severe storm potential overall. Showers will exit the southeast counties Saturday evening with much cooler/drier air arriving Saturday night into early next week. Expect high temps to be more in the 70s and lower 80s with low humidity through early next week. High pressure will lead to generally dry weather Sunday into early Monday, although it may be cool enough aloft on Sunday for some lake effect rain showers to form off of Lake Erie which could move into the northern tier of PA. There is now increasing confidence in a period of damp weather late Monday/Monday night, as a weak wave of low pressure rides south of Pa. The combination of this feature and high pressure east of New Eng is resulting in anomalous southeasterly flow in the GEFS output and will likely result in a period of rain/drizzle, especially over the southeast half of the forecast area. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... Low level southeast flow appears likely to persist into Tuesday, resulting in persistent low clouds and possible morning drizzle along and east of the Alleghenies. Med range guidance is in decent agreement into midweek, all of which push a dying cold front into the area Wednesday with a potential wave riding east across Pa on the stalled boundary Thursday. Have thus kept the chance of showers in the forecast both days, with the highest POPs during the PM hours. Model guidance diverges a bit toward the end of next week. However, latest ECENS and operational Canadian support the chance for another round of showers/tstorms with a cold front passage Friday. && .AVIATION /04Z SATURDAY THROUGH WEDNESDAY/... Some adjustments to the TAFS late this evening. Some showers and isolated thunderstorms been trying to work eastward this evening. Time of day and rain cooled air keeping conditions better east of the higher terrain so far. Earlier discussion below. For the 00Z TAF package, some minor adjustments to the fcst. Overall the earlier forecast good, especially with timing of the cold front on Saturday. Main changes were early on tonight and to add groups after 18Z on Saturday. Some high base showers this evening, with lower CIGS across the west. Also an isolated rumble of thunder for another hour or so. Improving conditions from west to east on Saturday afternoon, as winds shift to the west. Sunday looks mainly VFR and dry. Perhaps a few lower CIGS and a brief shower with the upper level trough and secondary cold front moving across the far north. Main area that could see lower clouds and a brief shower would be BFD early. Hopefully dry weather and VFR conditions would remain into Monday. Rather fast weather pattern for next week, with some chance for the warm and humid conditions to move back northward into the area by late Monday or Tuesday. Outlook... Sat night-Sun...VFR with no sig wx. Late Mon-Wed...More rounds of showers and storms possible. && .CLIMATE... Summer 2020 is on track for the warmest on record at Harrisburg with an average temperature of 78.1F month-to-date. August 2020 currently ranks 2nd warmest on record with an average temperature of 78.7F. 2016 holds the top spot coming in at 79.1F. Harrisburg has reached 90 degrees or higher 35 times since June 1st, including 1 day at 100F. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Steinbugl NEAR TERM...Fitzgerald SHORT TERM...Fitzgerald/Steinbugl/Travis LONG TERM...Fitzgerald AVIATION...Martin CLIMATE...Steinbugl
National Weather Service Eureka CA
254 PM PDT Fri Aug 28 2020 .SYNOPSIS...Warm temperatures will occur across the interior during the weekend, though slightly cooler conditions will be likely under areas of thick wildfire smoke. Otherwise, dry weather is expected during the next seven days, with a warming trend likely during early to middle portions of next week. && .DISCUSSION...Visible satellite imagery showed areas of thick smoke across portions of southern Trinity and much of Lake and Mendocino counties this afternoon. Surface heating has been reduced significantly as a result, and high temperatures were struggling to climb out of the 80s. Expect similar smoke conditions during Saturday afternoon, and thus reduced Saturday highs over Mendocino and Lake counties. Otherwise, the marine layer has mixed out across all coastal areas with the exception of Mendocino county, where a boundary layer eddy was focusing stratus development. Model guidance indicates stratus will redevelop tonight from roughly Humboldt Bay southward, and then dissipate during Saturday afternoon. Farther north, the Del Norte county coast may remain stratus free tonight due to the occurrence of dry northeasterly winds immediately above the surface. Going into next week...model guidance shows upper heights building over the West Coast. A warm deep-layer airmass is forecast to develop over NWRN CA as a result, including in the low-levels along the coast partially due to a slight offshore component in boundary layer flow. Hot temperatures in the 90s to low 100s will be probable across interior valleys, and heat risk concerns will exist. In addition, the marine layer is forecast to become progressively shallower during early to middle portions of next week, such that warm coastal temperatures in the 70s will be possible. && .AVIATION...Widespread haze and localized smoke linger over the region today, with significantly impacted visibilities in Mendocino and Lake counties. HRRR smoke guidance is suggesting visibilities in these areas will improve this afternoon as afternoon onshores push the smoke off toward the east, however somewhat impacted visibilities are expected for the remainder of the TAF period. Farther north in Del Norte and Humboldt counties, a smoky layer aloft is expected to remain in place while low-level gusty north winds pick up this afternoon, particularly at KCEC. The combination of smoky haze and haze from sea spray should continue keep visibilities down to MVFR through this afternoon at KCEC while skies stay clear. HIRES guidance is indicating a southerly wind reversal and associated northward surge of stratus this evening as strong northerlies build offshore, which should bring IFR to LIFR conditions to Redwood Coast tonight. /TDJ && .MARINE...Northerlies continue to RAMP UP to GALE FORCE through the weekend, strongest across the outer waters. Wind speeds are expected to moderately step up in intensity each day as high pressure builds over the NEPAC and the local thermal trough is deepened by afternoon heating, both acting to tighten the nearshore pressure gradient. The most significant step looks to occur on Saturday afternoon, when sustained wind speeds of 30 to 40 kts with gusts nearing 50 kts are expected to develop and persist through Sunday within the strongest wind core in the Northern Outers. These winds will generate seas of 14 to 18 ft across the outer waters in response, largest during the day on Sunday. GALE FORCE winds will likely reach close to the headlands of Point St George and Cape Mendocino, but otherwise model guidance indicates a sharp wind gradient toward the coast with significantly weaker winds nearshore, with HIRES guidance indicating possible overnight southerly wind reversals along the coast. Steep northerly seas propagate into all zones this weekend in response to these winds, and have lifted a Haz Seas warning for the Northern Inners starting tomorrow afternoon through Sunday to cover as the wind speeds and wave generation peak just offshore. The southern inners still look sufficiently protected in the lee of Cape Mendocino that an SCY should suffice, however steep and hazardous seas of 10 to 13 ft will plague Cape Mendocino through the weekend. Conditions look to significantly improve heading into next week as the high currently building over the NEPAC slips overhead and the pressure gradient relaxes, possibly bringing a period of widespread light-and-variable-mixed-with-rounds-of-southerly winds around mid- week. /TDJ && .FIRE WEATHER...Northeast winds gusting from 20 to 30 mph are forecast to occur across exposed ridges in Del Norte county tonight, and particularly Saturday night. Those winds combined with moderate to locally poor overnight humidity recoveries will aid in an elevated fire weather threat. && .EKA WATCHES/WARNINGS/ADVISORIES... CA...None. NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until 3 PM PDT Saturday for PZZ450. Hazardous Seas Warning from 3 PM Saturday to 3 AM PDT Monday for PZZ450. Gale Warning until 3 AM PDT Monday for PZZ470. Small Craft Advisory until 3 AM PDT Monday for PZZ455. Hazardous Seas Warning until 3 AM PDT Monday for PZZ475. && $$ Visit us at Follow us on Facebook and Twitter at: For forecast zone information see the forecast zone map online:
Area Forecast Discussion...UPDATED
National Weather Service Gray ME
1102 PM EDT Fri Aug 28 2020 .SYNOPSIS... An area of low pressure will bring beneficial rain to the area on Saturday with a few strong storms possible. An upper level trough will produce a few clouds and scattered showers mainly across the higher terrain Sunday with the rest of the region being breezy. High pressure will build in from Canada early next week for a period of dry weather possibly followed by some more rain midweek. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Update...Minor changes to reflect latest observational trends. Previous discussion...At this hour, RAP analysis shows a high pressure center shifting from Ontario into Quebec with its broad reach providing a mostly sunny and nice day locally. Meanwhile a northern stream trough is on its way out of the plains of Canada and will pick up an area of low pressure over the Great Lakes, strengthening it into tomorrow. Also of consequence is the remnants of what was Laura, starting its march up the Ohio Valley. Tonight, high pressure erodes and sinks southeast across Maine into the Atlantic as low pressure approaches from the west. Expect a pretty quick drop in temperatures especially over western Maine late this evening with dew points and sky cover relatively low. Clouds will increase through the night and gradually lower as a fairly deep layer of dry air erodes. Surface forecast charts suggest an ageostrophic northeast wind (read: cold/dry air dam) holds through the night roughly north of PWM which will keep PoPs low until a stronger band of warm frontal upglide arrives in the Connecticut River Valley in strengthening southwesterly mid- level flow just before dawn. Low temperatures tonight shake out to the 40s across the north to near 60 across the south. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... A complex area of low pressure containing post-tropical remnants and an extratropical circulation crosses the Northeast and Mid-Atlantic states Saturday, driven by a digging northern stream trough tracking through the northern Great Lakes region. As has been discussed in prior forecasts, CAMs and other higher- resolution models continue to suggest poor phasing between Laura`s post- tropical remnants and the northern stream low so while strong moisture availability is there, focused forcing continues to be an issue. Am anticipating plenty of haves and have-nots; rainfall rates will be relatively good given high PWATs but substantial accumulations will only occur where forcing, mainly in the mesoscale, can be wrangled. The main band of warm frontal rain crosses from SSW to NNE during the morning to mid-day hours bringing between 0.5-1" of rainfall where it crosses...highest in the Whites/western Maine mtns where low-level flow out of the south to southeast allows for some upsloping, and perhaps in embedded elevated convection. Behind this feature, in the warm sector (at least aloft), PWATs increase to 1.5- 2" but forcing remain fairly broad and unorganized. Instead, broad baroclinicity increases over the CWA as the surface warm front creeps north through southern New Hampshire and into extreme SW Maine through the middle of the day... so between surface-based instability and pockets of forcing with the frontal system itself am expected scattered to numerous showers and storms tomorrow afternoon with heavy rainfall. Overall am not expecting flooding issues except for on a very isolated basis with repeated storm activity or in areas of poor drainage. While thermodynamics remain fairly marginal... kinematics are fairly strong so stronger storms could produce strong, gusty winds...also cannot rule out a tornado, especially with the warm front. Dry air quickly enters in behind the system and cuts heavy rainfall threat for late evening and overnight...but showers remain possible for a little while longer as the upper trough rotates through. By early Sunday morning showers are relegated to the mountains in northwest upslope flow. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Low pressure will depart to our east on Sunday allowing for cool and breezy conditions with wind gusts around 25 knots likely in the CAA regime. Upslope stratocu will likely be present in the mountains, with clearer skies downwind. Monday and Tuesday look quiet with high pressure passing through the region from west to east. Some 12z deterministic and ensemble information indicate some potential for a rain event Wednesday as a southern stream wave moves northeastward from the Mid Atlantic. Several members keep this system far enough to our east to keep the area dry. Therefore, low confidence exists in the midweek forecast at this time. Thereafter, some signals point toward a frontal boundary stalled over our region Thu and Fri with the attendant chance for showers and thunderstorms. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Short Term...VFR prevails for the time being with gusty west winds today relaxing and going variable late this evening. CIGs gradually lower tonight into tomorrow morning with an approaching frontal system. -RA/RA, and perhaps an isolated thunderstorm, break out from the southwest by mid morning with MVFR and locally IFR conditions expected. This band crosses to the NE by early afternoon... then SHRA/TSRA becomes likely during the afternoon and evening. Storms could produce strong, gusty winds... with best probability of this occurring over southern terminals. Conditions gradually improve from west to east Saturday night, except for at HIE, with winds backing to the west and northwest. Long Term...MVFR in the mountains Sunday in stratocumulus. Westerly gusts to around 25 kt likely area-wide. VFR Monday and Tuesday with lighter winds. && .MARINE... Short Term...A broad area of low pressure with rain and a few storms will cross the waters Saturday into Saturday night. Onshore flow initially will turn offshore behind this system with seas building to around 5 ft over the outer waters. A SCA will likely be necessary, but it is marginal and there remains some uncertainty in timing. Long Term...SCA conditions increasingly possible for Sunday with westerly wind gusts around 25 kt. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Legro
Area Forecast Discussion
National Weather Service Houston/Galveston TX
654 PM CDT Fri Aug 28 2020 .AVIATION [00Z TAF Issuance]... Some evening showers and thunderstorms scattered across the inland flying areas are dissipating out now. By 01-02z, thunderstorms activity may transition to some showers for a bit, but VFR conditions will return across the TAF sites by 02z. Tonight may bring in some lower ceilings but mostly looking borderline and drier. Tomorrow will be VFR through the day with some chances of afternoon convection but much lower chances than today. 35 && .SHORT TERM [Tonight Through Tomorrow]... A trough of low pressure persists across SE TX and this feature coupled with high PW air has allowed for scattered showers and thunderstorms to develop this afternoon. The GFS and HRRR continue to be aggressive with shra/tsra this afternoon into the evening while other models are more benign. The ingredients are in place so will maintain chance PoPs through 01z and keep slt chance going over the W-NW zones through 03z. Activity should begin to wane once heating ends after sunset. Speaking of heat, 850 mb temps were very warm and cloud cover/winds last night blunted any cooling and the warm start has allowed temperature to reach the upper 90s by 1 PM. Dew points are not mixing out and the heat/humidity combo is producing oppressive and dangerous heat index values. Galveston reached a heat index value of 110 degrees by 10 AM and 114 degrees at 2 PM. Sugar Land reached a HI of 112 degrees by 2 PM and Angleton reached 110. Will maintain the Heat Advisory through 10 PM but the area should fall below criteria by around 800 PM. There should be some clearing by mid evening but more clouds will develop prior to sunrise and this coupled with winds not fully decoupling will yield another night of very warm temperatures. It will probably only cool into the upper 70`s inland and lower/mid 80s toward the coast. On Saturday, another warm start to the day and very warm temperatures aloft will translate to another day with oppressive heat. Have issued a Heat Advisory for Saturday as conditions look rather similar to today with dew points struggling to mix out coupled with warm daytime temperatures. Max Heat Index values will again exceed 108 degrees by late morning at the coast and by early afternoon further inland. Max Heat Index will range from 105 to 113 degrees. PW values drop considerably but briefly peak near 2.00 inches on Saturday afternoon. Could get a few showers and storms late but most of the area will probably remain dry. 43 .LONG TERM [Tomorrow Night Through Friday]... The forecast trend through the remainder of the weekend and into the beginning of next week will continue to be characterized by hot and humid conditions with potentially dangerous heat indices along with scattered to isolated showers and thunderstorms. Upper ridge will continue to build into the central CONUS by late Saturday, while broad surface high pressure across the Gulf and low pressures over the Rockies will promote low-level moisture advection. Global models continue to indicate a surge of higher (1.75-2.0+ in) PWs by Sunday evening, although ECMWF solution is more aggressive than other sources. Regardless, values should approach 90th percentile of observed climatology for nearby sounding sites, particularly surrounding Galveston Bay. With daytime highs expected to approach forecast sounding convective temps across the area, conditions will remain favorable for the development of diurnal showers and thunderstorms into the early part of the week. With the surge of moisture expected to peak on Monday, have included 40-50% PoPs. Daily activity should diminish upon the loss of daytime heating. We`re likely going to need to continue the Heat Advisories through the weekend, with daytime highs not expected to budge from the mid to upper 90s and maximum heat indicies remaining around 110 through Monday. Low temperatures, particularly along the coast, will not exceed the low to mid 80s, near daily record values. Given that these elevated nighttime low temperatures can exacerbate heat stress experienced during the day, it will remain imperative to take heat precautions in the coming days. ECMWF/GFS have come into better agreement regarding the departure of the prevailing ridge axis and approach of an upper trough as we head into the middle of next week with GFS now favoring the slower EC solution. A cold front extending from the associated surface cyclone remains on track to approach the CWA on late Tuesday/early Wednesday. Both solutions now show the surface boundary pushing into the northern counties, though a prolonged wind shift/temperature drop is not anticipated. Showers and thunderstorms associated with the approaching front could impact areas north of I-10 through Thursday. Have maintained slight- chance PoPs for now given current uncertainty. Cady .MARINE... Falling pressures in the lee of the Rockies and building surface high pressure over the eastern Gulf of Mexico will allow for a moderate onshore flow tonight. The flow will slacken early Saturday and veer to the SW as low pressure scoots across the southern plains. Winds will back to the SE as a weak sea breeze moves inland. The pressure gradient tightens again Saturday night into Sunday with onshore winds strengthening. A moderate to occasionally light onshore flow will persist through Wednesday with a lighter winds expected Thu/Fri as weak high pressure settles over the northern Gulf of Mexico. Re-issued a Coastal Flood Advisory for the bay facing shores of the Bolivar peninsula. Water was reported on a few roads in Crystal Beach. Overall, tides have returned to within a 1/2 foot of normal values along the coast. 43 .CLIMATE... The day is not complete yet so this discussion is preliminary and subject to change but the low temperature at GLS this morning was only 86 degrees and this would tie for the all time warmest overnight low temperature for this site (08/12/2020 and others). The city of Houston recorded a low temperature of 83 degrees and this would also tie for the warmest overnight low temperature for this location (6/23/2019 and others). Late afternoon storms could bring some rain cooled air so the low temps could change before the end of the day. 43 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 77 101 77 100 79 / 20 10 0 10 0 Houston (IAH) 80 98 79 97 80 / 20 10 0 30 10 Galveston (GLS) 84 93 83 93 84 / 10 20 20 40 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...Heat Advisory until 10 PM CDT this evening for the following zones: Austin...Brazoria Islands...Brazos...Burleson...Chambers...Coastal Brazoria...Coastal Galveston...Coastal Harris...Coastal Jackson...Coastal Matagorda...Colorado...Fort Bend...Galveston Island and Bolivar Peninsula...Grimes...Houston...Inland Brazoria...Inland Galveston...Inland Harris...Inland Jackson...Inland Matagorda...Madison...Matagorda Islands...Montgomery...Northern Liberty...Polk...San Jacinto...Southern Liberty...Trinity...Walker...Waller...Washington...Wharton. Heat Advisory from 10 AM to 9 PM CDT Saturday for the following zones: Austin...Brazoria Islands...Brazos...Burleson...Chambers...Coastal Brazoria...Coastal Galveston...Coastal Harris...Coastal Jackson...Coastal Matagorda...Colorado...Fort Bend...Galveston Island and Bolivar Peninsula...Grimes...Houston...Inland Brazoria...Inland Galveston...Inland Harris...Inland Jackson...Inland Matagorda...Madison...Matagorda Islands...Montgomery...Northern Liberty...Polk...San Jacinto...Southern Liberty...Trinity...Walker...Waller...Washington...Wharton. Coastal Flood Advisory until midnight CDT tonight for the following zones: Galveston Island and Bolivar Peninsula. GM...None. && $$ SHORT TERM...43 LONG TERM...Cady AVIATION...35 MARINE...43
Area Forecast Discussion
National Weather Service Wichita KS
627 PM CDT Fri Aug 28 2020 .SHORT TERM...(This evening through Monday night) Issued at 258 PM CDT Fri Aug 28 2020 Tonight-Saturday: Mainly minor tweaks to going forecast. Precipitation should develop in central KS later this evening as front approaches. There is a small chance for strong-severe storms, however there are only small areas at various times throughout the night where better wind profiles/shear and instability are co-located. Leaned toward combo of NBM and RAP time lagged data for this period for precipitation chances. Precipitation should slowly spread south during the night and on Saturday morning. With extensive clouds probable tomorrow, only modest temperature recovery, except possibly near OK border. This will significantly limit instability on Saturday, which was reflected in updated SPC day two outlook. Saturday night-Monday: Less clear how things will evolve with model consensus spreading precipitation area wide as surface low moves northeast and some 850MB moisture works north across western KS Saturday night. Better chances would seem more likely in far southeast KS, but confidence anywhere is not that high. Ultimately, with the west- north west flow aloft and return surface flow, would anticipate weak/diffuse dryline to develop somewhere just west of the forecast area with scattered very late night/early morning elevated precipitation. Main cold front now looks to move through on Monday morning, likely in the predawn hours in central KS. -Howerton .LONG TERM...(Tuesday through Friday) Issued at 258 PM CDT Fri Aug 28 2020 Unsettled weather is the rule as significant upper trough slowly moves across the area during this period. Considerable differences in the surface front location at the onset, with 1200 UTC ECMWF near I-40 and GFS roughly from KCNK-KDDC. Appears to be decent chance of precipitation for most areas early in period, but am increasing less optimistic after Tuesday, as most recent runs are trending drier or completely dry. If the drier solutions verify, temperatures on Wednesday-Friday would likely be a few to several degrees warmer than forecast. Of note, initialization grids/NBM were coldest of all solutions across central and south central Kansas for high temperatures on Wednesday and bumped up close the the 25th percentile. -Howerton && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 627 PM CDT Fri Aug 28 2020 A cold front will move southward across central and southern Kansas this evening/overnight. Scattered showers and thunderstorms are expected to develop just behind front and have indicated this with VCTS in the terminals. Otherwise, mainly VFR conditions are expected to prevail away from any convection. KED && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 72 76 63 85 / 30 50 30 30 Hutchinson 69 74 59 84 / 50 60 30 30 Newton 70 75 60 84 / 50 60 30 30 ElDorado 72 76 61 83 / 30 60 30 30 Winfield-KWLD 74 82 64 85 / 10 50 40 30 Russell 66 75 59 85 / 50 40 20 30 Great Bend 67 73 59 83 / 70 60 20 20 Salina 69 77 59 85 / 50 50 20 30 McPherson 68 74 59 83 / 60 60 20 30 Coffeyville 75 84 66 85 / 0 50 50 40 Chanute 74 79 63 84 / 20 50 40 40 Iola 74 80 62 84 / 20 50 40 40 Parsons-KPPF 75 82 65 84 / 10 50 50 40 && .ICT WATCHES/WARNINGS/ADVISORIES...None. && $$ SHORT TERM...PJH LONG TERM...PJH AVIATION...KED
Area Forecast Discussion
National Weather Service Indianapolis IN
1132 PM EDT Fri Aug 28 2020 .UPDATE... The AVIATION and Near Term Sections have been updated below. && .SYNOPSIS... Issued at 141 PM EDT Fri Aug 28 2020 Remnants of Laura will make their way across the southeast third of central Indiana today, and a cold front will bring the threat of isolated strong to severe thunderstorms tonight. Lingering showers will continue through Saturday morning with a lull in activity by Saturday afternoon except across the far southern counties. Nonetheless, the shower and thunderstorm threat will quickly resume again Sunday morning from the southwest as a weak upper trough moves in ahead of some warm air advection. && .NEAR TERM /Tonight/... Issued at 700 PM EDT Fri Aug 28 2020 Forecast looks on track with scattered dying convection currently over southern sections associated with the remnants of Laura and upstream convection over Iowa that could make it into the Lafayette area late this evening and overnight. The latter would appear to be the bigger concern with 50 knot mid level jet approaching from central Illinois and an increase in 850 millibar inflow combining to increase wind shear. Previous discussion follows... Issued at 141 PM EDT Fri Aug 28 2020 The effects of Tropical Depression Laura have been minimal across central Indiana so far as it spins into the western Tennessee Valley. Scattered showers and thunderstorms have been drifting through the forecast area throughout the day, but they have remained below severe limits with the main threat being some localized flooding. So far, the HRRR has been spot on this afternoon in regard to the convective trend. Showers and thunderstorms quickly spread across the southeast third of the forecast area earlier this afternoon, and current radar mosaic is showing some scattered activity from bands over northern and southwest portions of central Indiana. This, too, was well handled by the HRRR. As a result, confidence has increased in a lull in activity this evening into early tonight. Will not entirely pull Pops at this time, but will not rule it out with future forecast updates. At that point, focus then turns toward an approaching cold front from the northwest. It`s looking like this will be the best shot for any strong to severe thunderstorms. Without the diurnal heating though, it is questionable whether these storms will survive. But, if any do reach strong to severe levels, damaging winds will be the main threat. The time frame for the frontal passage will be between Sat 06-09Z across the northern portions of central Indiana to Sat 09-12Z across the southern counties. && .SHORT TERM /Saturday through Monday/... Issued at 141 PM EDT Fri Aug 28 2020 Low chances for showers and thunderstorms will linger through Saturday morning, but the afternoon will be dry across all of central Indiana. Meanwhile, the heat and humidity will make it feel like the mid to upper 80s. That trend will change on Sunday though as temperatures and dewpoints drop into the 70s and 50s, respectively. The dry weather will continue into Sunday for most of central Indiana, except the southern counties where some showers and thunderstorms will start infiltrating the area. This activity is expected to spread northeastward across the forecast area on Sunday evening and night with higher chances for more widespread activity on Monday. Temperatures through the period will generally be below normal. && .LONG TERM /Monday Night through Friday/... Issued at 141 PM EDT Fri Aug 28 2020 Chances for rain will continue for much of this period as the models suggest weak forcing features along with a warm and humid air mass available at the surface. ECMWF shows mainly a zonal flow in place on Monday night with a weak short wave passing across the Ohio Valley. Moisture appears to be a little limited as this feature passes Monday Night. Meanwhile additional weak short wave are depicted to be ejected from a deepening trough aloft over the western plains on Tuesday Night into Wednesday. Again confidence in this type of forcing mechanism is low...but low chance pops are still warranted. Best chances for rain look to arrive on Thursday as the previously mentioned upper trough will drift into the Mississippi Valley along with a cold front. At this point...several days of warm and humid southerly flow will have been in play across Indiana...providing plenty of moisture. Thus with this more organized forcing expected to chances appear to be on Thursday and Thursday night before dry weather returns with another high pressure system. && .AVIATION /Discussion for the 290600Z TAF Issuance/... Issued at 1132 PM EDT Fri Aug 28 2020 The impact of the remnants of Laura have moved off to the southeast of the terminals. Meanwhile, a cold front will drop southeast across the terminals 11z-15z. High Resolution Rapid Refresh and radar suggest some a few MVFR storms may drop down southeast along and ahead of the front. Otherwise, any MVFR ceilings will improve to VFR behind the front. Winds will be south and southwest less than 10 knots ahead of the front and northwest 8 to 11 knots or so behind it. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...TDUD NEAR TERM...TDUD/MK SHORT TERM...TDUD LONG TERM...JP AVIATION...MK
Area Forecast Discussion
National Weather Service Marquette MI
738 PM EDT Fri Aug 28 2020 .SHORT TERM...(This evening through Saturday) Issued at 336 PM EDT FRI AUG 28 2020 A quasi-stationary front remains draped west to east across the UP this afternoon with a well-pronounced short wave riding along it. SW 850 mb flow of around 25-35 kts nosing up to the boundary and then backing to SE is leading to a band of low to mid-level moisture convergence, theta-e advection, and fgen along the front. This morning`s NAM run had some beefy rainfall totals (2-3" in many areas) and while the instability isn`t there to support that rate of rainfall (and upstream obs and radar rainfall rate estimates confirm it is not happening) the NAM continues to have the best handle on the placement of the rain, as well as on how cool the temps are beneath this rain shield. Temps are mostly in the low to mid 60s where it is raining and in the upper 60s where it isn`t. They`ve likely already hit their highs for the day this morning everywhere except Menominee County where visible satellite shows the low-level stratus trying to erode somewhat. If it succeeds in doing so, temps could reach the mid 70s down there. The rest of the afternoon, the wave and associated surface low will continue riding east along the stationary front leading to continued moderate (occasionally heavy) rain. Relied on the experimental ESRL- HRRR for near-term POPs over the south-central as that seemed to be the only model picking up on the northward extent of the dry slot. It and the regular HRRR, as well as the NAM-nest and this morning`s NSSL-WRF, all develop thunderstorms in the clear warm sector over northern Wisconsin over the next couple of hours and race them east through Menominee County around 22-23z. However so far these aren`t materializing as satellite shows low stratus stubbornly hanging on across much of northern Wisconsin with little if any ice cloud that would indicate the beginnings of convective growth. Therefore, did not bite on that solution. Tonight, the rain should be exiting the east by midnight, but continued cloud cover and a few additional light showers will probably keep temps from falling to anywhere near as cool as the bias-corrected guidance advertises. After about 06z west and 09z central and east, models indicate a brief period of clearing that, being timed with peak diurnal cooling, could help lows get a little lower than they otherwise might. Still, only expecting low to mid 50s, even in the notoriously cool spots. Tomorrow a bowling ball closed upper low will dive southeastward across eastern Lake Superior. CAA with this wave will drop 850 mb temps to around 4-5 C by tomorrow evening which means another day of highs mostly in the 60s to perhaps low 70s south-central. Temps aloft are marginally cold enough to support lake-effect rain showers across the eastern half of the NW wind lake-effect belts, especially when combined with synoptic-scale lift from this vigorous wave dropping through. Model profiles show saturation from generally 900- 700 mb much of the day Saturday, and CAMs unanimously have showers, so felt confident enough to go with scattered showers across the east for most of the day. Elsewhere downwind of the lake there will be plenty of lake-effect clouds even in the absence of deep enough saturation for precip. The counties bordering the Wisconsin state line will probably be the only areas in the CWA to see much sunshine tomorrow. .LONG TERM...(Saturday night through Friday) Issued at 434 PM EDT FRI AUG 28 2020 Models suggest that a progressive pattern will prevail into next week. Mid level and surface ridging Sunday will give way to an approaching mid level trough and cold front Monday. A large scale trough will then linger into the north central CONUS and Great Lakes with the potential for additional precipitation chances. Temps near or slightly below seasonal averages are expected. Saturday night, cyclonic low level northerly flow with abundant 850- 750 mb moisture and 850 mb temps to around 6C (lake temps to near 20C) will support additional areas of light lake effect/enhanced rain/drizzle into locations near Lake Superior from Marquette county eastward. Otherwise, clearing over the interior west should allow temps to drop into the lower 40s, while readings into the lower to mid 50s are expected near Lake Superior and east. Sunday, any lingering light pcpn should diminish early even as clouds persist into the early afternoon. Mid level and and sfc ridging with low level drying and anticyclonic flow should bring clearing as winds veer to the east. Southerly flow will take over Sunday night ahead of the trough/front. Mon, 700-300 qvector conv ahead of the approaching mid level trough will support a band of rain moving through the region. Forecast instability is marginal for tsra, but may be high enough by the afternoon and evening over the east for a a few thunderstorms. Tue-Fri, the GFS/GEFS were more aggressive in bringing another large area of rain into the area supported by upper level div with the right entrance of a developing 250-300 mb jet. The ECMWF/ECENS keeps any pcpn with this feature farther south. As the mid level low settles over Hudson Bay, the models suggest another significant clipper shrtwv may drop into the area with increasing rain chances Thursday. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 737 PM EDT FRI AUG 28 2020 As rain ends at the TAF sites and pushes east, expect IFR conditions to remain until a cold front passes through each of the terminals later tonight. This front will weaken as it pushes east through the U.P., bringing the greatest amount of rainfall (and greatest effect on vis) at KCMX, followed by KIWD. The front may weaken so much that showers may develop and pass around KSAW later tonight. KIWD should see showers move in from 00z to 05z; the showers should move through KCMX between 05z and 07z, and KSAW may see showers in the vicinity between 06z and 08z. Once this front moves through, expect conditions to improve to VFR conditions for KIWD and KCMX. Thinking KSAW should have some low lying stratus/patchy fog that keeps the conditions at low MVFR until late Saturday morning. The passage of the front will lead to gusty NW winds developing during the day Saturday as well a return to cloud cover, but think even if there is a cig it will stay just high enough to keep things VFR, save maybe at KSAW, were there is a chance for some scattered showers that may bring cigs back down to MVFR. As usual, KCMX will be gustiest of the three terminals. Could see some 30-40 kt gusts there, especially by Saturday afternoon. KIWD should be the calmest TAF site in regards to winds and wind gusts. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 336 PM EDT FRI AUG 28 2020 A double-barreled low pressure system moving through the Upper Great Lakes tonight and Saturday will lead to a period of strong winds. Initially, E winds to around 20 kts are expected over the eastern half of the lake this evening on the northern periphery of one of those lows which will be passing south of the lake tonight. Then tomorrow the other low moves southeast through northern Ontario, just north of the lake. Cold air for this time of year with this low will lead to stiff NW winds developing late tonight from west to east across the lake, increasing to gale force Saturday morning on the east half. Thus, have maintained the Gale Warnings with this forecast package and did not need to alter the start and end times. Gales will subside to N winds around 20 kts Saturday night then become light and variable Sunday morning. But winds pick back up to 15-20 kts Sunday night out of the SE, veering to SW on Monday ahead of the next frontal system. SW winds 15-20 kts look to continue into the middle of next week behind the front. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Beach Hazards Statement from 6 AM EDT Saturday through Saturday evening for MIZ005-006. Lake Superior... Gale Warning from 3 PM to 8 PM EDT Saturday for LSZ267. Gale Warning from 10 AM to 6 PM EDT Saturday for LSZ244-264. Gale Warning from 11 AM to 8 PM EDT Saturday for LSZ266. Lake Michigan... None. && $$ SHORT TERM...RJC LONG TERM...JLB AVIATION...TAP MARINE...RJC
Area Forecast Discussion
National Weather Service San Francisco Bay Area
900 PM PDT Fri Aug 28 2020 .SYNOPSIS...Slightly stronger onshore flow will bring minimally cooler conditions to inland areas on Saturday, with gusty onshore winds possible during the afternoon and evening. High pressure will rebuild by early next week, resulting in drier and warmer conditions. Very warm to hot temperatures are expected inland from Tuesday onward next week. A shallow marine layer will linger near the coast and weak onshore flow should maintain milder temperatures near the ocean. && .DISCUSSION...As of 9:00 PM PDT Friday...Coastal profiler data indicate the marine layer depth has changed very little through the day, with the depth currently ranging from just over 1000 feet at Bodega Bay to around 1500 feet at Fort Ord. Evening water vapor satellite imagery shows a cyclonic circulation centered just west of Monterey Bay, which verifies the weak upper low models had predicted would develop in this area. The development of the upper low has thus far not had much impact on the depth of the marine layer. Even if the marine layer does not deepen over the next 12-24 hours, we will still likely see at least a few degrees of cooling on Saturday due to an expected increase in onshore flow. Also, the latest HRRR smoke model indicates this increased westerly low level flow on Saturday will result in a decrease in near-surface smoke concentrations by late afternoon. By Sunday, the upper low off the Central Coast is forecast to drift to the southwest as an upper ridge, centered over the Northeast Pacific near 45N/145W, begins to expand to the ESE and over northern California. This will likely result in the start of a warming trend on Sunday. A gradual warming trend is then forecast to continue through Tuesday as the upper ridge continues to expand and strengthen over California. Look for the marine layer to compress to less than 1000 feet early in the week, with its depth likely decreasing to 500 feet or less by Tuesday. 90s will become more common across inland areas by Monday and then become widespread by Tuesday. The warmest inland locations are forecast to reach or exceed triple digit temps by Tuesday. The models generally agree that at least light onshore flow will prevail throughout this upcoming warming trend. Thus, although coastal areas will experience warming, the magnitude of warming near the ocean is not expected to be as robust as inland areas. Most areas close to the ocean are forecast to remain in the 70s, although 80s are likely in some of the warmer coastal spots such as Santa Cruz and Big Sur by Tuesday. The center of the upper ridge is forecast to shift to our east by midweek, but still remain our dominant weather feature through the end of the week. As the ridge axis shifts to our east, we may see a slight uptick in onshore flow which would cause modest cooling near the coast during the second half of the week. But inland areas will likely remain very warm to hot throughout the week. Heat Risk next week is currently projected to remain in the moderate category except for isolated pockets of High Heat Risk in interior portions of our forecast area. Longer nights as we move into September will allow for more overnight relief from the heat. However, if models trend higher with daytime temperatures next week, we will likely see greater impacts due to more widespread elevated Heat Risk. && .AVIATION...As of 5:30 PM PDT Friday...For the 00z tafs. A mix of MVFR and VFR across terminals, with smoke and haze reducing vis across SF Bay area. Stratus lingers along the coast and has begun flowing into coastal MRY Bay. Marine layer has compressed a bit to about 1300 ft AGL, as per coastal profilers. Expect continued MVFR/VFR vis into the evening for SF Bay area as well as poor slant range vis. Overnight into Saturday morning, expect a range of VLIFR- MVFR in fog, stratus, wildfire smoke and patchy coastal drizzle. Stratus should clear out a bit earlier tomorrow morning with a more compressed marine layer. Continued onshore flow through tomorrow afternoon. Vicinity of KSFO...VFR conditions prevail through the evening, with possible intervals of MVFR vis. Winds NW at 17 kt, weakening overnight. Expecting MVFR/IFR cigs tonight after 10z, but earlier in North Bay and East Bay terminals. Clearing tomorrow around 18z. Continued lowered vis tomorrow morning and afternoon due to wildfire smoke and haze. SFO Bridge Approach...Similar to KSFO. Monterey Bay Terminals...VFR across KMRY and KSNS, with stratus pushing east of the bay. IFR cigs expected across terminals after 03z. Cigs lowering to LIFR/VLIFR overnight through Saturday morning with fog, stratus, smoke, and haze reducing vis. Cigs should begin to lift after 17z but lowered vis may linger into early afternoon. Winds 10-12 kt WNW becoming calm overnight. Continued onshore flow tomorrow. && of 08:00 PM PDT Friday...Gusty northwesterly winds will continue across the northern outer waters through the weekend and into early next week. These winds will generate steep fresh swell resulting in hazardous seas conditions, particularly for smaller vessels. Expect generally light to moderate winds elsewhere over the waters with winds gradually shifting out of the west to southwest along the coast tomorrow. Mixed seas will persist with a short period northwest swell and a longer period southerly swell. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...SCA...Pt Arena to Pigeon Pt 10-60 nm && $$ PUBLIC FORECAST: Dykema AVIATION: Lorber MARINE: AS Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion...CORRECTED
National Weather Service New York NY
1123 PM EDT Fri Aug 28 2020 .SYNOPSIS... A warm front moves north of the region overnight into Saturday morning. A frontal system will move through the area Saturday into Saturday evening. High pressure will build in on Sunday, with high pressure remaining nearby on Monday. A weak disturbance along with a warm front will approach from the southwest towards mid week. A cold front will approach Thursday night into early Friday and should clear the region in time for next weekend. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Adjusted POPs for showers, kept thunderstorms at slight chance but shifted chance to likely POPs late overnight (after 08Z Sat) and into early Sat Morning. This is similar to forecast reflectivity from the HRRR model. Adjusted temperatures slightly lower with current observed trends. Otherwise, forecast mainly on track. There is a better overall chance of shra and embedded tsra activity areawide mainly overnight and into early Saturday with the approach of northern stream shortwave and shearing post tropical Laura energy increasing lift and theta-e advection into the area, with focus along northward moving warm front. Potential for isolated stronger storms in a marginally unstable and modestly sheared environment near the coast. Will have to watch for any storms along the front, with enhanced helicity lending potential for rotating updrafts. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... A deepening northern stream closed low swings into the Great Lakes on Saturday, and then into New England Sat Night. The remnant upper level vorticity of Laura will get absorbed in the northern stream trough and swing towards the Mid Atlantic coast Sat afternoon. An accompanying surface low will take a similar track, with associated warm front lifting north Saturday morning, and then pre-frontal trough approaching Saturday afternoon. Numerous showers and scattered tstm development expected late Sat morning into Sat evening ahead of pre-frontal trough, in a very moist airmass (enhanced by remnant moisture from Laura), forced by approaching shortwave and weak llj ahead of trough axis. Deep layer shear is moderately strong, but in a weak skinny CAPE environment (weak mid-level lapse rates) with limited heating potential with morning and aft/eve convection. Overall this environment would present a potential for a few strong to severe storms (localized strong to damaging wind gust threat), but if we do get a few breaks of sun and better heating in the morning, the severe threat would increase. There is a localized flash flood threat from any training heavy downpours/convection in a very moist airmass (2-2 1/2" PWATs) Pre-frontal trough pushes east Sat eve, ending main shower threat, with a few localized showers possible with cold frontal passage passing Sat Night. Gusty NW winds and cooler and drier airmass advects in for Sat night. There is high risk of rip current development at Atlantic Ocean beaches on Saturday due to building 3 to 5 ft S wind waves on 15-20 kt SW flow, and a background 1 ft se swell. && .LONG TERM /SUNDAY THROUGH FRIDAY/... The cold front should pivot through later Saturday night leading to a drier northerly component to the flow into Sunday morning. Thus, high pressure is expected to build for the second half of the weekend leading to very nice weather along with lower dew points and more comfortable conditions. There is a moderate risk of rip current development on Sunday. Some uncertainty is now showing up among the global guidance beginning Monday night and into early Wednesday. As surface high pressure gradually retreats to the east and north the models are starting to show disturbances in the mid level southwest flow. The GFS is the most robust, thus it is showing more precip generally speaking during this time frame. This may be overdone based on potential feedback issues, as the other guidance is hinting at precip chances although not as robust as the GFS. Chose to go mainly on the lower end of chance POPs for Monday night through Tuesday night. Uncertainty still exists regarding precip and POPs for later in the period, namely Wednesday through the day on Friday. The upper level ridge will try to hold during this period, but the northern branch will attempt to get through and into the northeast at some point, more likely for late Thursday into Friday. For now kept mainly a diurnal trend for POPs and trended slightly higher with POPs further west and northwest. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Warm front associated with low pressure over the Great Lakes will move north of the region overnight into Saturday morning. The associated cold front approaches Saturday and moves across Saturday night. MVFR to IFR stratus has started forming for a few terminals. Mainly VFR conditions will eventually become more MVFR to localized IFR as rain showers return overnight into Saturday. S-SW flow subsiding to near 5-10 kt for the rest of tonight and into early Saturday. Winds return to a 10-15 kt S-SW flow Saturday morning through Saturday afternoon with gusts up to 20 kt. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Amendments will be possible for timing of any showers and thunderstorms as categorical changes late tonight through Saturday. Timing could be a few hours off from TAF. .OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY... .Saturday night...Winds becoming more W-NW 10-15kt with some gusts to 20 kt. Showers and thunderstorms taper off and VFR conditions eventually return. .Sunday-Monday...Mainly VFR. MVFR possible with a chance of showers late Monday night. .Tuesday...MVFR possible. A chance of showers. Slight chance of thunderstorms for western terminals Tuesday night. .Wednesday...MVFR possible. A chance of showers and a slight chance of thunderstorms with local MVFR. Detailed information, including hourly TAF wind component forecasts, can be found at: http:/ && .MARINE... Conditions stay below SCA criteria for tonight into Saturday morning. Seas possible to build to near 5 feet Saturday afternoon into evening due to strengthening SW wind fetch. Winds increase to 15-20kts with occasional gusts up to 25kts Sat. Winds shift out of the north west Saturday night into Sunday. Marginal SCA conditions are anticipated on the ocean through much of Sunday, especially for the eastern ocean on a northwest wind. The winds will then turn more to the north, and eventually northeast for Sunday night into Monday as winds and seas diminish further. Ocean seas are then expected to climb for later Tuesday and into Wednesday as the winds switch to the southeast along with an increasing south to southeasterly swell. Thus, the chances for small craft seas will increase during this time frame. && .HYDROLOGY... A widespread 3/4 to 1 1/4 inches of rain is likely tonight into Saturday evening, with locally 1-2 inches of rain possible in areas affected by multiple rounds of showers and thunderstorms. This will pose mainly a minor urban and poor drainage flooding threat, with a localized flash flood threat with training convection. At this time no hydrological concerns are anticipated through the remainder of the forecast period. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...High Rip Current Risk from 6 AM EDT Saturday through Saturday evening for NYZ075-080-081-178-179. NJ...None. MARINE...None. && $$ SYNOPSIS...JE/NV NEAR TERM...JE/JM/NV SHORT TERM...NV LONG TERM...JE AVIATION...JM MARINE...JE/JM/NV HYDROLOGY...JE/NV
Area Forecast Discussion
National Weather Service Pueblo CO
308 PM MDT Fri Aug 28 2020 .SHORT TERM...(This evening through Saturday) Issued at 238 PM MDT Fri Aug 28 2020 Currently... scattered showers and a few thunderstorms were noted over the high country at 2 pm this afternoon. Over the plains it was dry, with quite a bit of higher clouds along the I-25 corridor and mostly sunny out east. Temps around the region were in the mid 90s over the far eastern plains with generally 80s along the I-25 corridor. Over the mtns/valleys it was quite a bit cooler due to the clouds and showers, and readings were in the 70s San Luis Valley, to 50s and 60s mtns. This afternoon through tonight... Main concern is flash flooding potential for the burn scars, especially the Spring scar. Guidance continues to indicate the potential for heavier rain over the scars, especially over the Spring scar. Otherwise, SPC meso page is starting to show deep shear values increase as sfc winds shift to a easterly component, however CAPE values were meager along the I-25 corridor and mtns, with around 500 jules over the far eastern plains. I anticipate storms will continue to move northeast and gradually increase in intensity as the afternoon progresses per hi res NAM and HRRR guidance. Best overall chance for the heaviest rain still appears to be down along the Raton Mesa (including the Spring Burn scar area) and eastward to the KS/OK border areas. Areas N of highway 50 east of Fowler may not see all that much precip, except for eastern Kiowa county. Precip is going to be slow to move out of the plains this evening and will likely last into the early morning hours, especially over the far southeast Plains (greater Baca county area). Although some locally heavy rain will be possible, overall flood threat is low due to the antecedent dry conditons over the southeast plains. Tomorrow... Fcst area will continue to be under the threat of locally heavy rain and a couple of severe storms per national guidance products. Although shear will be stronger tomorrow, best low level forcing will over the far eastern plains by mid afternoon. so it will be this region which will likely see the best chance of severe storms. Overall precip chances tomorrow look quite good as guidance shows an cluster of storms moving across the region, with areas generally south of highway 50 having the best chances. Since areas south of highway 50 are likely going to see the heaviest rain today, potentially more heavier rain tomorrow may lead to local flooding issues. Given the better shear and CAPE projections for tomorrow over the far eastern plains, I believe we could see some larger hail and stronger winds then todays svr threat. .LONG TERM...(Saturday night through Friday) Issued at 238 PM MDT Fri Aug 28 2020 Finally, some model agreement for next week! The GFS has trended with the ECMWF for early next week, so forecast confidence is now increasing. It appears we will continue to have rain chances through Tuesday before drying out later next week. Saturday night into upper disturbance embedded in the flow will be moving across Colorado Saturday evening, with thunderstorms ongoing across the region. A few could be strong to severe in the evening with hail to near an inch in diameter and wind gusts to near 60 mph possible over the Plains. Locally heavy rainfall will be possible along with flash flooding on area burn scars and urban areas through the evening. Expect thunderstorms to shift eastward across the Plains in Sunday morning, clearing to the east late. On Sunday, an upper trough is forecast to pass to the north. Energy embedded in the flow aloft will lead to another round of afternoon and evening thunderstorms across the region. Limited instability should lead to less coverage and less rain efficiency. Storms will initiate over the Mountains, and spread east into the Palmer Divide and Raton Mesa region during the evening, before dissipating overnight. While less rain efficiency is expected, if a storm moves over a burn scar, especially if it receives heavy rainfall Friday and/or Saturday, flash flooding may be possible. A strong cold front will drop south across the Plains Sunday night into Monday morning. Monday and Tuesday...both the ECMWF and GFS have converged on a solution during this time frame. Both drop a strong upper trough south out of the Northern Rockies during this period. As the upper storm moves across the area, continued periods of showers and thunderstorms will be possible across the region. It would not be too surprising if by Tuesday, a few of the Central Mountain peaks above 13 kft have a light dusting of snow. As for the lower elevations, storms will form over the Mountains, and spread east across the Plains on Monday. As the upper system moves across Colorado, more widespread light rainfall is possible through Tuesday. One thing is for certain, it will be much cooler both days. After highs back around the lower 90s on Sunday, highs will fall about 20 degrees into the 70s and 80s for Monday and Tuesday. Wednesday through Friday...the upper trough is forecast to shift east into the Missouri, high pressure is forecast to build over the western states. This will put Colorado in dry northwesterly flow for the end of the week. The ECMWF builds the upper high east into Colorado, which would lead to warmer temperatures than are in the forecast. The GFS is less amplified with the upper high and keeps the warmest air to the west. It does appear that we will be dry during this period. Highs will most likely reach into the 80s with the GFS, while the ECMWF has us back into the 90s. Mozley && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 238 PM MDT Fri Aug 28 2020 Overall, expect VFR conditions during the next 24 hours at all 3 taf sites, KPUB, KALS and KCOS. Some TSRA will be possible at each of the sites later this afternoon and tomorrow afternoon, with brief mvfr possible as the storms move through. Gusty outflow winds will be possible with any storms near, or over, the taf sites. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...HODANISH LONG TERM...MOZLEY AVIATION...HODANISH
Area Forecast Discussion
National Weather Service Reno NV
148 PM PDT Fri Aug 28 2020 .SYNOPSIS... Isolated thunderstorms for eastern California and portions of western Nevada today are expected to retreat to near the Sierra Saturday. No storms are expected next week. Winds will remain relatively light until northerly winds possibly increase Monday with a dry front. Afternoon temperatures may fall to near average early next week; otherwise, they will remain mostly above average. && .DISCUSSION... * Main forecast points: - Periodic pushes of smoke with deteriorating air quality remains a concern for portions of northeast CA and western NV. - Isolated afternoon thunderstorms through Saturday, then dry. - Near to slightly above average high temperatures to soar to well above average, possibly near records, for late next week. Yup, more early morning thunderstorms out in Pershing and Churchill counties, this time east of Highway 95 and Interstate 80. Sometimes whole years go by without non-surface based/elevated storms in the summer and we have had at least 3 events in the couple weeks! The main forcing ahead of the disturbance responsible for the thunderstorms has shifted off into far northern and northeastern Nevada. However, a low-level theta-e maximum with a weak surface trough remains in west-central and northwestern NV, roughly along a line running from Pyramid Lake to Lovelock to Battle Mountain. This should be a focus for afternoon and evening showers and thunderstorms as daytime heating maximizes instability near the theta-e ridge. Elsewhere today, models do not have much of a signal for thunderstorms and it will mainly be reliant on differential terrain heating; therefore, isolated coverage at best is expected in the Sierra today with many areas not seeing anything at all. Any thunderstorms today do not look to move much so heavy rainfall is certainly possible along with gusty outflow winds 30-50 mph. As far as air quality, it has slowly improved for most spots per sensors noted on the AIRNOW page ( However, with the fresh influx of smoke particulates last night, ozone appears to be rising this afternoon as the sun works on the particulates. That is about all this forecaster knows about air quality science...please refer to air quality experts for a deeper dive into the details. In any case, HRRR simulations unfortunately continue to indicate another push of smoke tonight between ~7-10 PM, heaviest north of Lake Tahoe and Highway 50 in western NV. With this in mind, we have extended the dense smoke advisory through noon Saturday, and added areas north of Lake Tahoe, to highlight the expected degradation of air quality again tonight. Saturday, the focus for isolated showers and thunderstorms shifts to the Sierra, mainly south of Hwy 50, as weak deformation aloft combines with the standard higher terrain heating. Note that short-range, hi- res simulations as well as the GFS/NAM show minimal chance for thunderstorms Saturday afternoon...~10-15% at best per calibrated and/or ensemble based guidance. Still, will leave a low chance in there to cover any mid-afternoon to early evening pop-ups. Like a broken record, smoke may once again roll into western Nevada Saturday night as models show some westerly flow. Starting Sunday and running through next week, thunderstorm chances all but evaporate as strong high pressure over the north Pacific works its way over California and Nevada. Sunday through Tuesday, high temperatures look to ease down or at least remain somewhat in check as a dry backdoor front moves through the area Sunday/Monday. However, by mid to late next week, temperatures are expected to heat up in earnest as the ridge dominates the region. Highs in the 90s to low 100s are expected in the lower valleys, with a few records not out of the question. At least overnight and early morning temperatures should drop off decently given dry air, few clouds, and ever-lengthening nights as we move into September. Smoke`s impact on air quality remains a wildcard next week depending on fire activity and smaller-scale wind flow; however, a westerly evening wind remains possible given the strong heating in the Basin each day. -Snyder && .AVIATION... A couple of thunderstorms may develop near the Sierra Crest today, but the majority of thunderstorms should form out in the Basin and Range. Chance for a storm impacting a terminal today is about 15% at KLOL and 5-10% elsewhere. Outside of gusty outflow winds from isolated showers/storms today, the general low level winds will be northeast to east this afternoon with gusts under 20 kts. Thunderstorms for Saturday will shift to along the Sierra from Lake Tahoe south to Mammoth Lakes. Light northeast to east winds along with increased mixing have allowed visibility to improved somewhat this afternoon. Additional smoke transport will result in conditions worsening overnight through Saturday morning. -Edan && .FIRE WEATHER... A couple of storms may develop near the Sierra, but high resolution simulations have really backed off on that possibility for today. Better potential for isolated storms exists across the Basin and Range, where we are concerned about erratic and gusty outflow winds over 40 mph. Storms for Saturday will be confined mainly to the Sierra from the Tahoe Basin southward with drier and more stable conditions all areas by Sunday. The primary fire weather concern over the coming days continues to be the trough dropping down into the Great Basin and Rockies early next week. Model scenarios are still varying enough that warrant uncertainty with the winds, but central to eastern Nevada could see some gusty winds starting Sunday and Monday. For now the most gusty winds will be east of the Sierra Front, but it will likely still impact any ongoing fires across the Winnemucca dispatch areas. We are still keeping an eye on it as trough location could slide farther west resulting in stronger winds, even as far west as the Sierra. -Edan && .REV Watches/Warnings/Advisories... NV...Dense Smoke Advisory until noon PDT Saturday portions of NV002. Dense Smoke Advisory until noon PDT Saturday NVZ003. CA...Dense Smoke Advisory until noon PDT Saturday portions of CAZ071. Dense Smoke Advisory until noon PDT Saturday portions of CAZ072. && $$ For more information from the National Weather Service visit...
National Weather Service Charleston WV
1048 PM EDT Fri Aug 28 2020 .SYNOPSIS... Remnants of Laura pass overnight. Cool high pressure briefly builds in Sunday before more unsettled weather returns for next week. && .NEAR TERM /THROUGH SATURDAY/... As of 1045 PM Friday... Forecast in good shape this evening, and no changes needed at this time. As of 800 PM Friday... Forecast largely on track this evening. Previously mentioned boundary across northern WV appears to have drifted north over the past few hours as the influence from the remnants of Laura begin to take over. Based on recent radar trends, HRRR may be overplaying convective development thus far this evening. As such any flash flood threat appears to be decreasing. I still cannot rule out an isolated threat later this evening, but areal extent is small enough to forgo a watch. Remnants of Laura will move across the area overnight and be east of the area shortly after sunrise. Rainfall from the remnants should be manageable and largely absent of convective enhancement. Low stratus left in its wake will gradually lift and scatter as flow picks up ahead of approaching cold front. As of 415 PM Friday... Quick update to decrease POPs considerably over the next couple of hours in the wake of the activity across the northern Lowlands. Given the interaction with a southward moving boundary into southern PA and far northern WV, there may be additional backbuilding straddling our border with PBZ which may lead to isolated flash flooding over the next hour. Thereafter, latest runs of HRRR are trying to develop convection along the I79 corridor and points southward to the SE WV plateau along ML CAPE axis amid increasing moisture advection ahead of Laura, with additional development this evening along WV portions of route 33 and expanding eastward into the northern mountains. This corresponds where our most vulnerable counties are for flash flooding. I will monitor radar/satellite/HRRR trends over the next hour to see how things start to shake out. I may need to hoist a Flash Flood Watch for this evening across the aforementioned areas that were hard hit yesterday. As of 135 PM Friday... Made some minor upward tweaks to afternoon highs, otherwise forecast on track. Should continue to see convection blossom in an area of moist advection coupled with decent surface heating, mainly across southeast Ohio and north central West Virginia over the next few hours with additional storms developing in breaks in the clouds further south by 3-4 PM. As of 1230 PM Friday... Strong moisture advection into southwest Virginia, northeast Kentucky, and southwest West Virginia will continue to generate elevated showers and thunderstorms through the early afternoon. Further north and east, substantial breaks in mid-level cloudiness will allow for more substantial insolation and resultant building of surface based instability. As more favorable moisture advects into these areas, should see a blossoming of surface based storms through the afternoon hours. Deep layer shear generally at or below 25KTs across this area will limit overall potential for storm organization with the primary threats being localized gusty/damaging winds from wet microbursts and locally heavy rain. Training potential is significantly less than yesterday and storms are expected to be moving right along with storm motions around 25-30KT. This should help limit the overall flash flood threat and currently appears the heaviest cores will be generally west of an area of significantly compromised soil moisture holding capacity due to recent rain. Did strongly consider hoisting a flash flood watch for some of our northeast counties where 3 hr flash flood guidance values are 1 to 1.5 inches, but do not currently have enough forecast confidence with the aforementioned factors. Will still need to watch these areas very closely through this afternoon and evening. Shower and thunderstorm chances fade through the evening hours with steady rain associated with the remnants of Laura beginning to move into southwestern portions of the area around midnight. Overall, impacts are expected to be limited with an additional half to one inch of rain coming during mainly the early morning hours Saturday. The main area of concern will be limited to the aforementioned areas of low FFG with additional possible rain this afternoon. Some higher wind gusts will be possible, 20 to 30 mph, mainly across any more exposed ridgetops and in more favored isentropic down-glide off the higher terrain as winds aloft begin to shift more southerly heading toward daybreak. Remnants of Laura will largely exit the region to the east by mid-morning with largely dry conditions across much of the area from morning into early afternoon. A cold front approaches from the northwest during the afternoon hours yield a broken line of showers and thunderstorms. Severe potential will hinge on how quickly we can clear out and get some insolation down. High res model consensus suggests recovering enough to yield 1500-2000J/kg MLCAPE across portions of West Virginia in an an environment with 40KT deep layer shear which could yield some strong to severe cells in the line. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... As of 210 PM Friday... Remnants of Laura and cold front will have departed with a wholesale change in airmass filtering in with higher pressure. After the days of unsettled conditions, a day of stable air, slightly cooler temperatures, and dewpoints hanging out in the 50s will prevail. This will be short lived with the next upper trough and surface low developing over the Tennessee Valley. Surface low passes through Monday, bringing back the unsettled conditions with chances for showers/storms in southwesterly flow aloft. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 210 PM Friday... Likely to get waves aloft and a stationary boundary through the extended with another upper low digging into the lower Mississippi Valley. The degree of activity in the pattern will be largely dependent on the location of the stationary boundary, which the models are not doing well in covering on a solution yet. Expecting low level moisture to return to the region as well as September will begin on the more active side. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... As of 815 PM Friday... Remnants of Laura pass tonight with scattered convection this evening giving way to a general rain overnight. Bases will lower into MVFR and eventually IFR at most terminals. Predominately MVFR VSBY in rain, but brief IFR VSBY cannot be ruled out. System pulls east after 12Z with lingering low CIGS until late morning or midday as surface flow picks up and cold front approaches. Mountain terminals will likely hang on to low stratus a bit later. Cold front will move across with a narrow band of SHRA or TSRA and gusty winds in the afternoon. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing and extent of convection through 03Z may be more than forecast. CIGs may not lower into IFR as the remnants move across late tonight. 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 SAT 08/29/20 UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14 EDT 1HRLY 23 00 01 02 03 04 05 06 07 08 09 10 CRW CONSISTENCY H H H H H L H H L H H H HTS CONSISTENCY H H H H H H H H H H H L BKW CONSISTENCY H H H M H L M M M H H H EKN CONSISTENCY H M H L L L L L L L M H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H L H H H H H H H H AFTER 00Z SUNDAY... IFR valley fog possible Sunday morning. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...26/JP NEAR TERM...JP/30 SHORT TERM...26 LONG TERM...26 AVIATION...30
Area Forecast Discussion
National Weather Service Las Vegas NV
810 PM PDT Fri Aug 28 2020 .SYNOPSIS... Increasing chances for storms can be expected for the weekend as moisture filters in from the south across Mohave, eastern Clark, and eastern San Bernardino counties. Strong storms which could produce flash flooding and gusty winds will be possible. A Flash Flood Watch has been issued for central and southern Mohave County where more widespread flooding is expected. && .UPDATE...Another tranquil evening across the region but changes are on the horizon. A surge of moisture will work up the Gulf of California tomorrow with shower and thunderstorm chances returning to parts of the Colorado River Valley and Northwest Arizona. Already seeing some mid level moisture getting entrained into the flow with this afternoons 00z VEF sounding showing a small moist layer near 600mb. Current HRRR guidance seems a bit bullish developing some late night shower activity out of this pocket of mid level moisture but some virga activity may pop in the early morning hours mainly south and east of Las Vegas. Made some small tweaks to the cloud cover grids tonight but otherwise no major changes needed. -Outler- && .SHORT TERM...Currently, a pattern is unfolding that is supportive of flash flood potential for areas where storms develop on Saturday. High pressure located to our east will slowly sink southward toward northern Mexico as low pressure continues to spin near the central CA coast and larger trough moves into the PacNW. In between these two features a weak jet will set up across northwest AZ and southern NV. Add in a gulf moisture surge fortified by Tropical Depression Hernan near the tip of Baja and we have a portion of our area with a favorable set up for storms capable of producing flash flooding as well as strong winds. PWATs will increase northward going into Saturday with the 1.00 in PWAT line cutting through central Clark into central San Bernardino County and across the AZ Strip. The moisture gradient will be quite tight just to the north of this boundary as PWATs drop to around 0.5 inches across the southern Great Basin and Inyo County. The jet will provide upper level support and a decent amount of wind shear to work with on Saturday along with 1000-1500 J/kg CAPE values which could support some organized complexes of storms. Best chances for storms remain across Mohave County where we have decided to go with a Flash Flood Watch for central and southern portions of the county. This is where moisture, forcing, and instability will all be in place for higher coverage of flash flood producing storms. However, strong storms producing localized flash flooding will be possible outside of this area as well. With upper level support and little change in available instability, activity could continue through early Sunday morning across Mohave County. Storm chances will continue on Sunday but will be dependent on what transpires tomorrow and tomorrow night. If it looks like another active day is in store, the Flash Watch Flood may need to be extended or expanded. As moisture increases this weekend temps will moderate as a result, dropping a few degrees from today`s high temps. .LONG TERM...Monday through Friday. On Monday, a mid-level trough will dive down from the PacNW through the Great Basin to the southern Plains. Not much wind to speak of with its passage but it will push moisture southward out of the area and storm chances will be limited to the furthest southeast corner of our area of responsibility Monday and Tuesday. Temps will continue on a downward trend, bottoming out on Monday with high temps right around seasonal normals which means around 100 degrees for Vegas. A strong ridge builds in behind this trough and temps will rebound for the second half of the work week with dry conditions. && .AVIATION...For McCarran...Winds will shift from south to southwest this afternoon at speeds of 10-15 knots gusting near 20 knots. South to southwest winds will continue overnight at 8-10 knots before becoming breezy out of the south to southwest once again on Saturday afternoon. Storms will be possible to the east across Mohave County and the Colorado River valley with best chances for any outflows in the valley after 00z Sunday. For the rest of southern Nevada, northwest Arizona and southeast California...Breezy, southwest winds will continue through this evening with gusts of 20-25 knots possible. This wind pattern will again be present on Saturday. Storms will develop Saturday afternoon with highest chances across Mohave County and lower chances over the Colorado River Valley and the eastern half of San Bernardino County. There are low chances for storms to directly affect any of the terminals but outflow are possible at all terminals less KBIH. Storms could potentially last through early Sunday morning for Mohave County. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ SHORT TERM/LONG TERM...Guillet AVIATION...Guillet For more forecast information...see us on our webpage: or follow us on Facebook and Twitter