Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/11/20

Area Forecast Discussion
National Weather Service Bismarck ND
853 PM CDT Tue Mar 10 2020 .UPDATE... Issued at 853 PM CDT Tue Mar 10 2020 Fog/stratus imagery loop and surface-925mb observations show a weak low circulation between Bismarck and Flasher. High resolution models still forecasting stratus and patchy fog to evolve between Bismarck and into the James River Valley 04z-09z. Satellite indicates a developing area of stratus/patchy fog from Wishek to Ashley, and looking at webcams at both locations, it appears that this is indeed developing. Will add some mention of patchy fog, although it will remain progressive in nature per HRRR/RAP/GFSLamp guidance. As mentioned, the stratus and fog will be exiting by 09z as warm air advection/vertical motion increase along with westerly winds just above ground level. All of these elements will promote drying conditions through the low level column. Otherwise, warm air advection west with cirrus overspreading western and central North Dakota will continue for the rest of tonight. UPDATE Issued at 548 PM CDT Tue Mar 10 2020 Latest radar and water vapor imagery loop shows a weakening shortwave over south central North Dakota, approaching the James River Valley. As expected, lightning has been decreasing over the last hour. Will continue to monitor this as it shifts east this evening. Low clouds over northeastern South Dakota are forecast to move into and through the James River Valley early tonight, from 04z-09z. Current forecast looks good. && .SHORT TERM...(This evening through Wednesday) Issued at 237 PM CDT Tue Mar 10 2020 The main concern in the near term is scattered rain/snow showers and the potential for isolated thunderstorms across south central North Dakota this afternoon and evening. An upper level trough is passing through the Northern Plains this afternoon, with low level warm air advection underneath. This forcing has led to scattered showers across western into south central North Dakota this morning and early afternoon. This snow has been much heavier and longer lasting than expected. We received reports of around 2 to nearly 4 inches from near Grassy Butte to Killdeer. As of 215 PM CDT, the precipitation was centered near Lake Sakakawea. While downstream surface temperatures are near 40, dewpoints are still around 30, so think that a wet-bulb effect could cool temperatures enough for precipitation to remain mostly snow. Confidence on how long this snow will continue and remain impactful is very low. Further south, satellite and radar show scattered showers developing along and south of Interstate 94. Multiple consecutive runs of the RAP have shown CAPE approaching 500 J/kg nearly overlapping with 40 kts of 0-6 km bulk shear in an area enclosed by Highway 85, Interstate 94, the Missouri River, and the South Dakota border. Therefore, it seems reasonable that these showers may evolve into isolated thunderstorms through the afternoon. Regardless of whether these showers contain lightning, BUFKIT momentum transfer suggests gusty winds as high as 45 mph accompanying the showers. This activity is forecast to dissipate this evening as it enters a more stable air mass east of the Missouri River. There could be a change over back to snow before the precipitation completely ends, with little to no impacts expected. A light southwesterly breeze and at least scattered cloud cover will keep temperatures warmer tonight, with much of western and central North Dakota seeing lows in the lower to mid 30s. Some models are suggesting fog development from south central into eastern North Dakota tonight, but winds just above the surface seem a bit too strong, so will leave this out of the forecast for now. For much of Wednesday, western and central North Dakota will be under the warm sector of a clipper system moving from central Saskatchewan into southern Manitoba. Most areas outside the James River Valley and Turtle Mountains will see highs in the 50s. Models have trended farther south with this system and have sped up the cold front arrival in northwest North Dakota to as early as mid afternoon. There could be some rain showers along the cold front as it moves through. Also, expect breezy conditions on Wednesday. .LONG TERM...(Wednesday night through Tuesday) Issued at 237 PM CDT Tue Mar 10 2020 The main concern for the long term period is increasing chances for accumulating snow this weekend. By the middle of the night Wednesday, the cold front will have moved through the area. Thursday will be cooler, with highs mainly in the 30s. Some models are suggesting the potential for flurries mainly across northern North Dakota on Thursday under cyclonic flow aloft, but the probability is not high enough to include in the forecast at this time. Colder air will continue to filter into the region on Friday, ushering in a prolonged period of weather more typical of winter. The main feature of concern is a strong closed upper low that is forecast to land on the Pacific Northwest coast by Friday night. Downstream strong isentropic ascent in tangent with right entrance region jet dynamics is forecast to result in snow developing across western North Dakota as early as late Friday night. What happens beyond this remains unclear. The GFS and ECMWF are persistent in showing different solutions through early next week, and their respective ensembles support the deterministic solutions. The GFS shows a stronger, more progressive wave bringing several inches of snow to much of western and central North Dakota. Meanwhile, the ECMWF is slower and weaker, and even advisory level snow is in question. What is becoming more certain is that it will snow somewhere at some point this weekend into early next week. But details on how much, exactly when and where, and the degree of impacts remain very uncertain at this time. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 548 PM CDT Tue Mar 10 2020 LIFR cigs are expected at KJMS between 04z-09z Wednesday,otherwise VFR cigs/vsbys are forecast for the remaining terminals this taf period. Low-level wind shear at or below 1000ft above ground level has been added to all terminals except KMOT. This is associated with a warm front that will mostly impact KXWA/KDIK/KBIS between 09z-17z Wednesday, and KJMS from 21z through the end of the period. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KS SHORT TERM...Hollan LONG TERM...Hollan AVIATION...KS
Area Forecast Discussion
National Weather Service Charleston SC
900 PM EDT Tue Mar 10 2020 .SYNOPSIS... High pressure will persist offshore into late week. A cold front could move into the region Friday night before stalling over the weekend. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... No major changes were made for the mid-evening update. Both the RAP and H3R keep a risk for isolated showers lingering for much of the night, but both have been too aggressive in their respective simulated reflectivity products so far tonight. 11/00z CHS raob depicted a rather dry profile with PWATS less than an inch. Gridded pops 5-10% look reasonable for now. Lows in the mid- upper 50s look on track. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... Wednesday: There is decent model agreement that an advancing mid level short wave will intercept an axis of modest instability (both surface-based and mid level). This should result in scattered showers and a few tstms developing across inland zones during the afternoon. These convective rains will sweep into the coastal zones by late day or early evening and offshore Wednesday night. Higher rain chances appear to be north of I-16 and mostly across Southeast SC. We see mixed signals for any risk of severe tstms, however very dry layers above 700 MB and chances for ML CAPES exceeding 500 J/KG are both on the low side, suggesting severe convection is unlikely. The GFS was an outlier on the 12Z/10 model run with higher deep- layered instability and greater convective QPF. We bumped POPs into the 40 percent range along our northern tier of zones. Highs will be warm in the mid 70s north to around 80 south with partly cloudy skies. Thursday and Friday: A warm and moist airmass will remain in place during the period as high pressure lingers offshore. Occasional weak shortwaves will move through Thursday into Friday, potentially producing isolated showers at times. Highs should continue to warm with Friday likely the warmer day ahead of backdoor cold front on Friday night. We nudged highs up to around 80 north to almost the mid 80s to the south of I-16 in GA. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... A backdoor cold front will approach the area late Friday afternoon, stalling over or just south of the area through early next week. Slightly cooler temps and better rain chances are expected. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... VFR. Extended Aviation Outlook: Localized risk for flight restrictions as convective rains move through the coastal corridor late Wednesday and Wednesday Evening. Patchy low clouds and fog possible Thursday morning and perhaps low cigs in the wake of a backdoor cold front this weekend. && .MARINE... Tonight: High pressure offshore will lead to mainly S to SW winds around 10 kt. Seas will be in the 2-4 ft range, possibly as high as 5 ft in the far out reaches of the Georgia offshore waters late. A S to SW flow will persist Wednesday through Friday. SCA conditions are not expected during the time period across near shore waters. We could see a brief period of 6 ft seas closer to the Gulf Stream Wednesday Night over outer GA waters. Models are still divergent in the progress of the backdoor cold front Friday night into the weekend. Some NE surging is possible over South Carolina waters during this period and we may end up seeing some SCAs during latter periods. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$
Area Forecast Discussion
National Weather Service Cheyenne WY
916 PM MDT Tue Mar 10 2020 .UPDATE... Issued at 911 PM MDT Tue Mar 10 2020 Since wind speeds have decreased across Central Laramie County, including Cheyenne, we have decided to cancel the High Wind Warning there a few hours early. The rest of the High Wind Warnings will continue. && .SHORT TERM...(This evening through Wednesday) Issued at 218 PM MDT Tue Mar 10 2020 A westerly flow aloft with a few shortwaves embedded within the flow and minimal surface instability has lead to a breezy, warm day, with a few clouds overhead, and some light showers and a lightning strike or two over the southern Panhandle. A few light snow showers over the mountains west of the Laramie Range are still possible, but will decrease in probability over the next few hours and taper off this evening. Have seen an increase in subsidence aloft that has allowed for strong winds at 700 mb to mix down to the surface for windy conditions across the High PLains and through the gap wind ares of southeast Wyoming. As winds increased this morning and looked to overachieve, issued a High Wind Warning for the wind-prone areas, and expanded it into central Laramie County, mainly to capture the northern area of the county, where Bear Creek has been gusting close to High Wind criteria for a few hours. Across the High PLains, also saw temperatures rise a few degrees over the forecasted high, and minimum humidities drop more than expected due to winds coming off of the Laramie Range, causing compressional heating for areas along and east of the I-25 corridor. With this in mind, and knowing that a northern clipper is expected to descend out of the north tomorrow for increased surface gradients and therefore stronger winds at the surface, have issued the HIgh Wind Warning out through Thursday morning for all zones included in the Warning today, except for the central Laramie County zone. Also, winds will gust up to 30 mph across the Panhandle, with low humidities - achieving Red Flag Warning criteria across the western Panhandle for the afternoon period, where all fire weather zones have been converted to "ready." This means that any fires started tomorrow across the Panhandle may spread quickly and be difficult to put out. Meanwhile, to the west of the Laramie Range, the clipper will draw moisture out of the southwest once more, and a wintry mix of rain and snow is expected to fall across the Sierra Madre and Snowy MOuntains, in addition to the lower elevations of Carbon County. Precipitation will be light with only an inch or two of accumulation possible over the peaks. The wintry mix will limit this accumulation however. As the disturbance descends south over the High Plains, will see the wintry mix fall across the region as far south as a line extending from Converse County out through Dawes County, including the North Laramie Range and its foothills to the east, by daylight Thursday morning. The High Wind Warning will end around this time as gradients shift and subsidence gets cut-off. .LONG TERM...(Wednesday night through Tuesday) Issued at 218 PM MDT Tue Mar 10 2020 A passing cold front exiting the forecast area by Thursday morning will bring a chance of light snow across mainly the northern half of the CWA as lighter accumulations of up to an inch across the high plains may be possible. This snow will likely not linger too long as daytime highs on Thursday reach into the upper 30s and low 40s and given the recent warm temps and lack of overall support for heavy snowfall rates not overly concern with any prospective headlines at this time. Focus quickly turns to Friday as an upper level closed low gets absorbed in the overall troughing pattern. This amplified wave will then eject eastward as precipitation chances increase through Friday afternoon into Sunday. Moisture transport from the Gulf of California should provide decent atmospheric profile saturation that will enable further dendritic growth aloft and subsequent snowfall amounts. Given the progressive nature of the system and how the EURO and GFS have the wave impacts reach our area still remains somewhat disjointed. Given the slight disconnect, concern moving into the weekend will be where the heavier snowbands occur along with the transition of the rain/snow line as some wintry mix cannot be ruled out completely. This forecast for the weekend will need to be watched as we get closer due to any prospective impacts to area travelers across both states and snow/ice concerns. Moving into the tail end of the weekend, broad pacific coast trough pattern sets up with embedded waves following the atmospheric flow with multiple rounds of light to moderate precipitation chances possible along with cooler Canadian air settling in for a perhaps dreary, cooler string of days to start the week. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 516 PM MDT Tue Mar 10 2020 Lingering showers on the latest KCYS radar are moving away from KSNY as breezy winds become the main story through the overnight and majority of Wednesday. CONSSHORT picking up on some LLWS from KSNY through KLAR overnight while the RAP, GFS, and HRRR are picking up on stronger winds aloft though soundings have it still fairly gradual in rise. Have bumped up winds at terminals overnight and into Wednesday with gusts into the mid 30 kt range. && .FIRE WEATHER... Issued at 218 PM MDT Tue Mar 10 2020 Gusty westerly winds coming off the Laramie Range have contributed to warmer temperatures, and lower humidities today than previously forecast. As winds overachieved and mixed down from aloft, a High Wind Watch was upgraded to a Warning and expanded to other zones. This is a sneak peak of what we expect to see tomorrow as a stronger system moves out of the north tomorrow, with increased winds, and therefore, lower humidities, and higher gusts forecast for WEdnesday afternoon. High temperatures will also increase. Have issued a Red Flag Warning for Wednesday afternoon to cover the threat as fuels are now ready across the western Panhandle. Will see a pattern change and increased humidities and lowered temps towards the end of the week and into the weekend. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...High Wind Warning until 6 AM MDT Thursday for WYZ106-110-116-117. NE...Red Flag Warning from noon to 7 PM MDT Wednesday for NEZ311>313. && $$ UPDATE...RUBIN SHORT TERM...AB LONG TERM...WM AVIATION...WM FIRE WEATHER...AB
Area Forecast Discussion
National Weather Service Dodge City KS
648 PM CDT Tue Mar 10 2020 ...Updated Aviation Section... .SHORT TERM...(This afternoon through Wednesday night) Issued at 1145 AM CDT Tue Mar 10 2020 Remaining stratus is eroding rapidly as of midday, leaving only scattered cirrus embedded in the westerly zonal flow aloft. A pleasant early spring afternoon, warming into the 60s east and 70s southwest, with modestly breezy south winds. Winds will trend light SEly by early evening, with NAM/HRRR agreement placing a surface low near Boise City, Oklahoma. A shortwave will dive through Kansas tonight. 12z NAM, HRRR and various other CAMs are in excellent agreement forecasting scattered convective development across the NE/east zones late this evening through midnight. NAM forecasts a modest instability axis across these zones by late this evening, with MUCAPE to near 500 J/kg near Larned ranging up to 1500 J/kg in the Barber county vicinity. Surface moisture quality will be limited, typical of early March, with dewpoints generally in the mid 40s. Yet, steep mid level lapse rates and dynamic lift ahead of the arriving shortwave yield high confidence in convective development. Shear will support primarily elevated, weakly rotating updrafts, capable of hail to the size of dimes to quarters. Included thunderstorms in the grids from Hays to Larned, St. John to Pratt to Medicine Lodge. Convection will initiate near the eastern CWA border, but confident any convective organization will be relegated to Wichita`s CWA zones late tonight. Marginal 5% hail probability from SPC is warranted. A northerly wind shift/cold front will progress southward across SW KS tonight behind the departing shortwave, with gusts of 25-30 mph. These northerly winds will be very brief in duration, with winds trending light and variable around sunrise Wednesday. Sunrise Wednesday temperatures ranging from mid 30s north to mid 40s south. Wednesday will feature near-perfect spring weather, with mild temperatures and light winds beneath benign zonal flow aloft. All locations will warm to within a few degrees of 70 with a mix of sunshine and cirrus. Get outdoors and enjoy! Models depict another very weak shortwave Wednesday night/early Thursday, with an increase in cloud cover and the potential for additional rain showers favoring the eastern zones. Milder temperatures Thursday morning, holding in the 40s. .LONG TERM...(Thursday through Tuesday) Issued at 209 PM CDT Tue Mar 10 2020 Despite a pronounced shift to north winds, another pleasant spring day is expected Thursday with continued dry weather. A dry cold front will usher in modest cooling at 850 mb, cooling temperatures most noticeably across the northern zones, with far northern zones holding in the upper 50s, still near 70 along the Oklahoma border. A big change to cloudy and much cooler on Friday. Strong closed low over southern California 7 am Friday will weaken to a negatively-tilted progressive trough near the Four Corners 7 pm Friday. As this weakening system approaches, energizing SW flow aloft will send copious Pacific moisture over the plains, with a thick overcast expected. Simultaneously, broad cool surface high pressure across the northern/central plains will continue to push a much cooler airmass into SW KS, with a pronounced easterly, increasingly moist upslope boundary layer flow. Between these two mechanisms, clouds will be extensive Friday. 12z ECMWF shows pronounced 850 mb cooling, trimming to near 0C at 850 mb at DDC Friday afternoon. With no sun, afternoon temperatures will struggle in the lower to mid 40s. High confidence regarding a significant round of precipitation, centered on Friday evening. Models continue to show strong dynamic lift overspreading SW KS Friday evening, ahead of the approaching shortwave trough axis. Plentiful Pacific moisture will combine with an open gulf, generating widespread measurable rainfall. Today`s run of the NBM came in very wet, with widespread 90% pop grids. These were accepted, with 12z ECMWF depicting strong QPF signals across all zones Friday evening. High confidence on precipitation occurring. Some questions linger regarding rain versus snow. NBM/GFS solutions are notably colder, with current forecast showing rain changing to snow across the western 1/2 of SW KS (higher terrain) Friday night. 12z ECMWF 850 mb thermal fields are warmer, and argue for mostly rain, actually showing warm air advection into the southern zones during the heaviest rain. This is a reverse from several runs ago, when ECMWF was colder. All of this to say, phase change uncertainty remains with this expected round of beneficial precipitation. Progressive trough axis will be east of SW KS midday Saturday, with all SW KS zones dry by Saturday afternoon. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 644 PM CDT Tue Mar 10 2020 Overall, the aviation weather will be fairly tranquil for this TAF period. The only exception may be up at the HYS terminal late this evening as we will be monitoring development of showers and thunderstorms around that terminal toward 03Z. Any showers/thunderstorms in vicinity of HYS will only last an hour or two late this evening before pushing east deeper into central and south central Kansas where the greater organization and strength of thunderstorm activity will be overnight. A fast-moving front will sweep south, providing a bump in wind speed to 12 to 15 knots out of the north-northeast. These winds should not last long, 3 to 5 hours or so, before falling quickly down to 6 knots or less and remaining light the remainder of the TAF period. && .PRELIMINARY POINT TEMPS/POPS... DDC 41 70 46 65 / 10 0 10 0 GCK 38 70 44 64 / 10 0 10 0 EHA 42 69 46 69 / 0 0 0 0 LBL 43 69 45 69 / 0 0 0 0 HYS 39 69 44 60 / 30 0 20 0 P28 45 70 49 70 / 50 0 10 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Turner LONG TERM...Turner AVIATION...Umscheid
National Weather Service Eureka CA
355 PM PDT Tue Mar 10 2020 .SYNOPSIS...Warm and dry conditions will continue through Friday afternoon, with well above normal interior temperatures expected. Cooler, showery conditions are expected over the weekend, with accumulating snow possible along many travel corridors as well. && .DISCUSSION...High pressure has reclaimed California, and as a result, warm and dry conditions with mostly sunny skies can be expected through at least Thursday, and possibly Friday as well. Interior locations are likely to see high temperatures climbing into the 70s and perhaps near 80 in some parts of Mendocino County each day, with temperatures inching toward 60 along the coast. Overnight, while temperatures will gradually begin to increase through the week, efficient radiational cooling will likely mean that interior valleys will continue to be chilly, with patchy frost likely as well. Another frost advisory has been issued for tonight and Wednesday morning across portions of northern Mendocino and northern Lake Counties as a result. Friday is expected to be mostly warm and dry as well, although a very slight cooldown is likely as a storm system is expected to approach the area from the north. Model guidance appears to be converging on a more common solution for this storm, which will bring much cooler air and showers to the region Friday night through at least Sunday, and possibly Monday. While confidence is high that much cooler temperatures are expected, and that precipitation is not expected to be particularly heavy from a liquid perspective, there is considerable uncertainty regarding how much snow will fall and at what elevations. However, there is potential to see snow falling as low as 1500 feet in elevation by Saturday, which would impact numerous local highway passes over the weekend. In addition, convective showers may also be capable of producing accumulating small hail. This showery, unsettled weather is likely to continue through late Sunday, and may linger into Monday if the storm system is slow to exit to the south. /BRC && .AVIATION...Mostly VFR conditions are expected to prevail across the area over the next 24 hours. The one fly in the ointment is the possibility of some low ceilings around the Humboldt Bay area prior to daybreak Wednesday as indicated by the high resolution HRRR model. Although there is no indication of clouds in these areas as yet, it is possible due to low-level moisture pooling along the coastal terrain N of Cape Mendocino. Is is uncertain whether any ceilings would fill in over KACV, so have included a scattered low deck for now. The combination of dry air and light offshore flow overnight should keep visibilities mostly VFR at coastal TAF sites, and there is no indication of any low clouds creeping up the Russian River Valley into KUKI. Some afternoon and evening wind gusts to near 20 knots are possible today along the Redwood Coast, particularly at KCEC. Otherwise, low-level winds over land are expected to be generally light. /SEC && .MARINE...Northerly winds and seas will continue to trend upward this evening as the coastal pressure gradient tightens in response to high pressure building offshore. Small Craft Advisory conditions over the offshore zones will expand to the nearshore waters north of Cape Mendocino this evening as seas continue to build and propagate into the inner waters. The southern nearshore zone will likely remain a bit more sheltered over the next few days, precluding the need for an advisory at this time. However, localized strong winds and rougher seas will likely still be found in the typical locations near and downwind of the Cape. Have went ahead with Gale Warning for the northern outer waters for Wednesday afternoon as recent guidance has trended a bit stronger with winds over the next few days. The small craft advisory for the northern inner waters may need to be extended if the trend holds. Seas will be dominated by wind-driven, short-period waves which will likely rise above 10 feet by later Wednesday given the duration of the northerly wind regime. Multiple small swells will also move through the waters in the next few days, including a long-period S swell of about 2 ft and a pair of mid-period NW swells on the order of 3-4 ft. Expect a brief break in the northerly regime this weekend as the next system approaches from the northwest, although seas will likely be slower to come down. && .EKA WATCHES/WARNINGS/ADVISORIES... CA...Frost Advisory from 1 AM to 9 AM PDT Wednesday for CAZ110-111- 114. NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until 3 PM PDT Wednesday for PZZ470. Gale Warning from 3 PM Wednesday to 4 AM PDT Friday for PZZ470. Small Craft Advisory until 9 PM PDT Thursday for PZZ450. Small Craft Advisory until 9 PM PDT Thursday 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
National Weather Service Fort Worth TX
701 PM CDT Tue Mar 10 2020 .SHORT TERM... /NEW/ /Through Wednesday Evening/ Afternoon surface analysis reveals a 1016 mb low over the Nebraska Sandhills, with a broad warm sector south of this low across much of the Southern Plains. Dewpoints have surged into the 60s across much of our CWA. DFW Airport recorded a high temperature of 80 F this afternoon, making today the warmest day since February 2, 2020 when the high reached 81 F. Waco on the other hand, only reached a high of 73 F as cloud cover persisted for much of the afternoon. Tonight, we will see temperatures dropping into the mid 60s. Light winds, temperatures cooling to near their dewpoints, and subsidence aloft will favor the development of areas of fog, particularly across Central Texas. A Dense Fog Advisory may be required again tonight in our southern two or three tiers of counties. For now, will wait on the next round of high-resolution model guidance, but portions of Central Texas look like they`ll probably see visibility low enough to necessitate an advisory. Fog and low clouds should lift gradually during the morning hours, but cloudy skies will likely persist into the afternoon. Late in the afternoon, there is a significant amount of uncertainty with regards to convective potential. A few of the high-resolution models (most notably the HRRR) develop isolated to widely scattered thunderstorms across parts of North Texas, including in and around the Dallas/Fort Worth Metropolitan Area. Other models keep the modest cap in place and develop nothing at all. Backing up and looking at the bigger picture, upper-level support will be limited at best. Despite this, we will have a weak cold front sliding into North Texas during the late afternoon. This front could provide enough low-level convergence and ascent to kick off a few thunderstorms, much like the HRRR is suggesting. For this reason, opted to include slight chance to chance PoPs, with the highest PoPs indicated near and northeast of Fort Worth. In terms of severe potential, this is obviously highly conditional on thunderstorms developing in the first place. Should thunderstorms develop, steep mid-level lapse rates and surface dewpoints in the mid to upper 60s will support CAPE values of 1,000 to 2,000 J/kg. In addition, moderate deep-layer wind shear on the order of 40-50 KT will be present. This parameter space would permit whatever thunderstorms that do manage to develop to become strong to severe, with large hail and gusty outflow winds being the primary hazards. The cold front should dissipate over North Texas and retreat north as a warm front late in the evening, decreasing shower/thunderstorm chances. The bottom line for Wednesday afternoon and evening is that thunderstorms are not very likely. If thunderstorms do develop however, they may be able to become severe, with large hail and damaging winds being the main threats. Folks across North Texas (particularly near and north of I-20, and near and east of I-35W) will want to keep an eye on the weather, just in case. The most likely time for any thunderstorms would be between the hours of 4 p.m. and 10 p.m. Godwin && .LONG TERM... /Issued 218 PM CDT Tue Mar 10 2020/ /Wednesday Night onward/ Bottom line up front...the weather pattern across North and Central Texas looks to remain unsettled through the weekend into early next week. Expect period of rain showers and isolated thunderstorms as surface cold fronts move through North Texas and southwest flow aloft brings moisture and several shortwaves to generate episodes of showers/isolated thunder. The overall long range pattern and model solutions suggest that the very large and strong upper level low near southern California will stall and become elongated as the weekend approaches. As this happens...the prevailing upper level flow across Texas is expected to remain southwesterly with sufficient moisture content for showers and isolated thunderstorms. As the southwest flow persists...the models depict a cold front stalling across North Texas by Friday. Showers and thunderstorms are possible Thursday afternoon/evening with some limited potential for strong/severe storms north and east of the DFW area. The exact location of this front will be important with respect to precipitation as the southwesterly flow aloft moves over the slope of the stalled front. Another round of showers/thunderstorms associated with the next upper level wave is expected late Sunday mainly northwest of the DFW area and along the Red River. The next cold front/surge moves into North Texas by Tuesday with continued southwest flow aloft and showers/thunderstorms are expected to continue through mid week. KV && .AVIATION... /NEW/ /00Z TAFs/ Concerns: MVFR CIGs, IFR vsby at KACT. Wednesday afternoon/evening convective potential in/near D10 TRACON. CIGs have managed to improve to VFR at KACT after cloudiness persisted for much of the day. Expect all sites to see lowering CIGs after 06Z, with MVFR likely to begin during the pre-dawn hours. Areas of BR/FG are likely across parts of Central TX, with IFR vsby likely at least intermittently at KACT. CIGs/vsby should improve at all sites by 17Z. Late Wednesday...isolated to widely scattered TSRA may develop across parts of North TX. Confidence is too low to mention explicitly in TAFs, but if TSRA do develop, most likely locations would be near and northeast of KDFW with some impacts to the Bonham arrival gate possible. TSRA would diminish after 04Z. Godwin && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 64 81 66 85 60 / 0 10 30 20 50 Waco 63 80 63 84 63 / 0 10 10 10 40 Paris 61 77 63 79 57 / 0 10 30 40 70 Denton 63 81 65 85 57 / 0 10 30 20 50 McKinney 63 79 65 83 58 / 0 10 30 20 60 Dallas 64 81 66 84 60 / 0 10 20 20 50 Terrell 63 80 63 81 60 / 0 10 20 20 50 Corsicana 63 80 63 80 63 / 0 10 10 10 40 Temple 61 80 63 82 63 / 0 10 10 5 30 Mineral Wells 61 81 63 85 57 / 0 10 20 10 40 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$ 37/26
National Weather Service Hastings NE
959 PM CDT Tue Mar 10 2020 .UPDATE... Issued at 959 PM CDT Tue Mar 10 2020 HRRR continues to indicate the potential for dense fog, especially for areas along and north of a line from Minden to Geneva in Nebraska. A Dense Fog advisory has been issued until 10am for those locations. Some areas of freezing dense fog is possible where temperatures may drop to 32 degrees or below. UPDATE Issued at 642 PM CDT Tue Mar 10 2020 The HRRR and SREF guidance continues to indicate the potential for fog tonight especially after midnight through the morning hours Wednesday. Have taken a more bold approach on the forecast extending it across much of the area. Right now, have not increased it to dense fog, but the potential is definitely there. Will continue to monitor for potential Fog headline. && .SHORT TERM...(This evening through Wednesday) Issued at 344 PM CDT Tue Mar 10 2020 Radar shows a few returns in the far northeast part of the area yet this afternoon. They will soon be moving out of the area. Satellite shows a clearing line with the western part of the forecast area with partly cloudy skies while the east is still cloudy. The temperatures are warming up where there is a little more sunshine, but the rest of the area remains on the cool side. Have cooled things off a little bit for this afternoon, but expect that the sunshine continues to spread to the east and temperatures will warm some. There is a weak upper level wave that moves into the area tonight. Clouds are expected to move back into the area and some of the models bring in some mainly spotty precipitation for the evening. Not all of the models have precipitation and those that do have very light or spotty precipitation for the area. Have lowered PoPs a little, but wonder if there is more in there than will actually happen. There will be some instability that could bring some thunder to the area. Expect that all of the precipitation will be ending around midnight or a little after. The next concern will be fog. The edge of the lower deck of clouds has been slow to move out and there could be some fog tonight. Will go with the idea that the lower clouds will move out of the area this afternoon/evening and will move back with some fog later tonight. Have the fog in the northeast, but will need to see if that is far enough. If the clouds do not move out, there may be fog further to the west. Fog will linger into Wednesday morning, but should move out better during the day. With sunshine and warm advection, expect temperatures to be warmer on Wednesday. .LONG TERM...(Wednesday night through Tuesday) Issued at 344 PM CDT Tue Mar 10 2020 Wednesday night through Thursday night there is a weak wave that will move through Wednesday night. There is a chance for there to be some light rain late Wednesday night as a weak cold front moves through the area. Thursday will be a little cooler behind the cold front. The period Friday through Saturday is expected to be fairly busy. A surface high builds into the area Thursday night with colder air building into the area ahead of an approaching upper level low. The models continue to have differences in the timing and how the system moves through. The ECMWF is much faster than the GFS with precipitation across the area on Friday. It may be a little fast, but believe that there will be something around and there will be some time to fine tune it as it gets closer. The models are a little closer for the Friday night into Saturday time frame that there will be quite a bit of precipitation around the area. The next question becomes weather type. The models still have fairly warm temperatures during the day on Friday and Saturday, so it starts off with some mixed rain/snow, but changes to rain during the day time, with more of mixed or even snow during the night. The problem is, some of the forecast highs are quite a bit higher than some of the raw model data. Would not be surprised to see some lower temperatures as this period gets closer. Saturday night through Tuesday should continue to be fairly busy. The first wave moves out and Saturday night should be dry, but another weak wave moves in with some warm advection. Expect there to be some precipitation with the warm advection. The temperatures will continue to be cool enough during the night that there will be some snow, but during the daytime there may be some rain. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday) Issued at 642 PM CDT Tue Mar 10 2020 The primary aviation concern is the potential for fog tonight...some could be dense. The HRRR and SREF guidance continues to indicate the potential for fog tonight, especially after 06z with the potential for some dense fog. Have really taken a pessimistic direction for the 00z TAFs with that line of thinking. IFR conditions through the overnight hours could become LIFR if dense fog does indeed become reality. Confidence is increasing on this fact, but for now...I`ve kept visibility in the IFR range. Will need to watch for amendments and for 06z TAFs for updates. Additionally there continues to be a chance for some showers and thunderstorms tonight. The high-res guidance continues to indicate that KGRI has the best potential for this to occur, so have a VCTS in KGRI only for a couple hours this evening. && .GID WATCHES/WARNINGS/ADVISORIES... NE...Dense Fog Advisory from 1 AM to 10 AM CDT Wednesday for NEZ039>041-046>049-061>064-074>077. KS...NONE. && $$ UPDATE...Billings Wright SHORT TERM...JCB LONG TERM...JCB AVIATION...Billings Wright
Area Forecast Discussion
National Weather Service Jacksonville FL
800 PM EDT Tue Mar 10 2020 .UPDATE...Isolated showers have formed along the the west coast seabreeze this evening as models have indicated. Expect shower activity to dissipate before midnight with mild temperatures overnight. Late night fog possible as clouds have decreased over the area with passage of shortwave trough aloft. .AVIATION...VFR conditions will prevail tonight and Wednesday. Patchy fog possible over inland ne Fl between 08z-12z at GNV and VQQ may result in brief MVFR/IFR vsbys. Winds will be light from the sw at 5-10 knots Wednesday morning...becoming se during the afternoon near the east coast. && .PREV DISCUSSION [354 PM EDT]... .NEAR TERM [Through Tonight]... Atlantic sfc ridge continues to be positioned just north of the area and will shift south and southeast through tonight. As result, low level winds currently southeast will weaken and become more southerly during the day. Upstream, model guidance shows a shortwave trough over AL/central and nrn GA pushing eastward which should reach our area later this morning and aftn. Radar shows a swath of rain and showers associated with this trough. This feature along with weak low level convergence will support a low chance of showers (about 15-25 percent) for southeast GA today. Further south, model blends, including GFS/ARW/NMM and the HRRR suggest a few showers over inland northeast FL this aftn. A few showers also expected offshore waters near a sfc trough. Though mid and high clouds will be prevalent today until the early to mid aftn hours, southerly flow will support highs in the mid to upper 70s, with coastal areas being limited to lower to mid 70s due to onshore flow. Tonight, shortwave trough is expected to push offshore of our coast while multilayered clouds continue into the evening hours. With lack of meaningful forcing for showers, will go back to POPs of around 5-10 percent tonight. Also, anticipate an improvement in cloud cover overnight. Lows again will drop toward the mid and upper 50s. Some patchy fog will be possible inland northeast FL zones. .SHORT TERM [Wednesday Through Thursday Night]... Another upper level shortwave will move aloft of the Tennessee Valley tomorrow, reinvigorating the weak front to our north, then moving off the east coast tomorrow night. The frontal boundary will be close enough in proximity to our northern GA counties that there may be some isolated showers or thunderstorms, though widespread convection isn`t anticipated. The cold front is expected to stall out again tomorrow night, keeping the area on the warm side of the boundary through Thursday night. Temperatures will peak in the low 80s both afternoons, then dip to the mid- upper 50s at night. .LONG TERM [Friday Through Tuesday]... Mid and upper level ridging will build over the northern Gulf coast and southeastern CONUS Friday, bumping the stalled frontal boundary across central AL-GA northward a bit. Meanwhile, a potent upper level +PV anomaly will move into the desert southwest Friday, then race northeastward into the Plains Saturday, weakening as it lifts into the Tennessee Valley Saturday night. This more potent system will launch a front across the Plains and into the Tennessee Valley, but keep storms to mostly to our north, with only a 20-30% chance of storms around Monday for southeast Georgia. The mid and upper level ridging will build over the Florida Peninsula around mid week, with low level ridging to our east keeping the area under light southerly flow. Daytime temperatures will be toasty, peaking in the mid 80s, with upper 80s possible in north-central Florida. Lows will be in the upper 50s to low 60s. .AVIATION... [Through 18Z Wednesday] VFR conditions expected through today with abundant passing mid and high clouds with only brief restrictions to MVFR possible at times under diurnally driven cumulus field. Prevailing SE winds will continue near 10 kts or less with the potential gusts near 15 kts along coastal terminals this afternoon with east coast sea breeze. Best potential for afternoon showers will be near SGJ and later afternoon into the evening near GNV where sea breezes will merge. Winds decouple this evening with lingering low clouds. Potential for restrictions tonight after 06z due to low stratus and fog with highest probabilities near GNV and VQQ at this time where trended toward IFR at GNV and MVFR at VQQ after 08-09z. After sunrise Wed, prevailing VFR with SSW winds increasing to 4-8 kts under low/mid clouds. .MARINE... An approaching weak cold front will stall to our north tomorrow, with a ridge of high pressure sitting off to our northwest. This will keep light winds from the south and low seas in place through much of the period. This weekend, another cold front is poised to approach the region, though at this time, winds are expected to remain below 15 knots. .FIRE WEATHER... A cold front approaching the area today will stall out to our north tomorrow, keeping a warm, humid air mass in place for the next few days. Afternoon RH values will only dip to around 40% for the next several days, precluding any red flag conditions. With the front in closer proximity tomorrow, transport winds will increase in GA, leading to high dispersions Wednesday afternoon. .HYDROLOGY... River flooding will continue to impact most mainstream basins across SE GA this week. Moderate flooding will continue along the Altamaha from Charlotteville to Everett City. Everett City has reached a broad crest today of 16.6 ft, which the second highest on record (at less than .2 ft shy of the highest record) and only .4 ft shy of Major flood. The Satilla in Waycross (in Moderate flood) is falling to Minor this afternoon while the Satilla at Atkinson is in Minor flood and approaching its crest. Big forecast changes for Alapaha near Statenville which was in Action stage early this morning, with this location forecast to rapidly rise late this week (Fri Mar 13) to Major flood. Interests in the Alapaha basin should very closely monitor river forecasts this week. Significant rainfall is not expected, river levels are runoff from rainfall that occurred over central GA last week. && .PRELIMINARY POINT TEMPS/POPS... AMG 57 78 58 80 58 / 10 20 10 0 0 SSI 57 72 59 73 59 / 10 10 10 0 0 JAX 58 80 59 82 59 / 10 10 10 0 0 SGJ 59 77 58 79 59 / 10 20 0 0 0 GNV 57 81 55 83 57 / 20 10 0 0 0 OCF 59 80 56 83 58 / 20 20 0 0 0 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...High Rip Current Risk until 3 AM EDT Wednesday for Coastal Flagler-Coastal St. Johns. GA...None. AM...None. &&
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
936 PM CDT Tue Mar 10 2020 .UPDATE... Issued at 934 PM CDT Tue Mar 10 2020 Low clouds have been slow to erode across the area since sunset and latest RAP soundings are showing moisture may stay trapped the rest of the night under developing inversion. Going forecast was already cloudy ahead of shortwave trough dropping southeast out of the northern Plains. Did not change going precipitation forecast much as there should not be much more than a few sprinkles in the north with the shortwave trough. Still looks like a MCS will develop over the Central Plains tonight and drop southeast through southern Missouri into the Mid South. The southern part of the CWA will see showers and few thunderstorms associated with this late tonight into tomorrow morning based on the latest RAP mass fields and the CAMS runs. Made minor adjustments to winds and temps based on cloud changes and latest observations. Britt && .SHORT TERM... (Through Late Wednesday Night) Issued at 323 PM CDT Tue Mar 10 2020 A cluster of thunderstorms is expected to develop late tonight to the southwest of the CWA, namely over southeast Kansas and far southwestern Missouri. This complex should head southeastward through Wednesday morning, with the far northeastern edge of the rain shield just clipping our far southern counties on Wednesday morning. For the vast majority of the CWA, just an increase in cloud cover is expected. After the morning threat of rainfall in parts of southeast Missouri, the remainder of the day should be dry with subsidence in the wake of the earlier midlevel disturbance. Low- level moisture increases late Wednesday night, and combined with an incoming shortwave trough, slight chance/chance PoPs for rain showers are in the forecast for the late night hours. Mild temperatures will continue through the short-term forecast period, especially at night. Lows each night are forecast to be well above the freezing mark, generally in the 40s. Highs on Wednesday should be 5-10 degrees warmer than today, due to decreasing cloudiness and low-level warm air advection. Look for temperatures to top out in the upper 50s to mid 60s. Warmest conditions are most likely across portions of central, east-central, and southeast Missouri. Gosselin .LONG TERM... (Thursday through Next Tuesday) Issued at 323 PM CDT Tue Mar 10 2020 (Thursday) Chances of rain showers, and some thunderstorms, will increase ahead of a cold front on Thursday. Currently, the best chances for rain appear to be across east-central and southeast Missouri as well as southwest Illinois during the afternoon where the strongest low- level convergence and upper-level jet support is expected to reside. There also may be a narrow temporal/spatial window for a few strong/severe storms in some of our southeastern counties. While deep-layer shear is quite strong, the instability is the main question mark as models suggest below 1000 J/kg of MUCAPE. Going SPC marginal risk looks good, and we will continue to monitor trends with respect to instability over the next 24-36+ hours. (Thursday Night - Friday) A quiet period of weather is forecast to end the work week as a strong Canadian area of high pressure at the surface slowly moves into the Upper Midwest. Dry weather along with a return to near normal temperatures is favored. (Friday Night - Saturday Night) Another round of precipitation is likely Friday night through Saturday night. A cold rain is most likely across the area, but am watching northern sections of the CWA for the possibility of snow at least mixing in with the rain either or both Friday night/Saturday morning and Saturday night when surface temperatures are coldest. The airmass that will be in place ahead of this system is definitely Canadian and seasonably cold/dry. This combination should bring at least a threat of snow across northeast Missouri and west-central Illinois, as dry air in place helps cool the column as it saturates. Accumulations may even be possible if the timing is just right and the snow comes down at a heavy enough rate to coat the ground. Right now however, the best chances are just north of the CWA as suggested by the EPS/GEFS means. Regardless, this should not lead to any big impacts, but is a reminder that it is mid March and winter may not be completely over. (Sunday - Next Tuesday) Another short-lived quiet period is likely on Sunday as dry weather is favored along with near to below normal temperatures. More active weather looks to return for early next week as a deep trough carves out across the western CONUS with a stalled baroclinic zone somewhere across the mid-Mississippi Valley. The bottom line is expect a wet period with several rounds of showers, and potentially some thunderstorms. Temperatures should also moderate through the end of the extended forecast with highs back in the 60s by next Tuesday. Gosselin && .AVIATION... (For the 00z TAFs through 00z Wednesday Evening) Issued at 619 PM CDT Tue Mar 10 2020 MVFR ceilings are expected to move out of the terminals between 00-02Z. Then dry and VFR conditions are expected the rest of the period. There is some possibility of MVFR ceilings moving back into the St. Louis area terminals late tonight into early Wednesday, but confidence is too low to include in the TAFs at this time. Winds will remain light through the period. SPECIFICS FOR KSTL: MVFR ceilings are expected to improve to VFR by 01Z. Then dry and VFR conditions are expected the rest of the period. There is some possibility of MVFR ceilings moving back into the terminal late tonight into early Wednesday, but confidence is too low to include in the TAF at this time. Winds will remain light through the period. Britt && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX
Area Forecast Discussion
National Weather Service Marquette MI
744 PM EDT Tue Mar 10 2020 .SHORT TERM...(This evening through Wednesday) Issued at 416 PM EDT TUE MAR 10 2020 WV imagery and RAP analysis indicated a nearly zonal pattern through the northern CONUS with an upstream shortwave trough into the western Dakotas. At the surface, ridging prevailed through the western Great lakes with light winds and plenty of sunshine. Mid clouds were increasing from MN into western WI with WAA/isentropic lift ahead of a trough through the Western Plains. Tonight, expect clouds will continue to move in and thicken ahead of the approaching shortwave. Some light snow will also develop overnight as 285k-290k isentropic lift with weak to moderate 700-300 qvector conv associated with the shrtwv moves through. However, given the moderate dynamics and moisture inflow and the strongest forcing to the south of Upper Michigan, accumulations will be light, generally around an inch or less, greatest over the south and east. Wednesday, mid level and sfc ridging are expected to take over with any remaining snow over the east ending early. Enough dry air will also move in with partial clearing allowing temps to rebound into the upper 30s to lower 40s. .LONG TERM...(Wednesday night through Tuesday) Issued at 346 PM EDT TUE MAR 10 2020 The long-term period starts out with punctuated precip chances through week`s end, with Thursday being the day most likely to see precip. Initially, southerly flow at the surface and warm air to the west will allow for WAA to be ongoing through the overnight period tomorrow into Thursday morning. Under this regime, a generally non-diurnal temp curve looks to occur tomorrow night, with the coolest temps of the night occurring early in the west, with a general warming trend from west to east as the night progresses. However, with widespread cloud cover overhead, the temp differences won`t be extreme, moderating temps throughout the night. For Thursday, which looks to be the most impactful day of the long-term period, there are some fairly significant differences amongst the models with respect to how quickly the colder air advects in behind a cold front associated with a deepening low over northern Ontario. Therefore, have trended toward more of a blend of precip types, predominantly a rain/snow mix, as the colder airmass attempts to work its way in. With that warmer air potentially taking a bit of time to completely dissipate from the surface, and given that we`re inching ever so closer to spring with a more favorable sun angle, have snow (mixing with rain) mention for Thursday but little to no accumulation expected. As this timeframe gets closer and models *hopefully* come into better agreement on the timing of colder air arriving, better refinement in these finer details should be more easily achieved. By Thursday night, the precip should be transitioning completely over to snow, especially by early Friday. As mentioned, precip chances will linger through the end of the traditional work week, with a ridge moving in over the weekend to clear things out. The next precip chances look to move in early next week as a shortwave looks to move through. Temperatures on Thursday may rise well into the 40s before falling throughout the day from west to east, with closer to normal temps anticipated for Friday into Saturday. The warming trend looks to ramp back up later in the weekend, with a general trend to rise back above normal for mid-March. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 743 PM EDT TUE MAR 10 2020 An approaching disturbance should bring MVFR cigs and some -sn to KSAW overnight. There is a small potential that cigs could fall to IFR. The -sn will exit Wed morning, followed by MVFR cigs scattering out by early aftn. The -sn will likely pass s of KIWD/KCMX, and VFR conditions should prevail thru the fcst period at both terminals. That said, there is a low potential that MVFR cigs could appear for a time late tonight/Wed morning. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 416 PM EDT TUE MAR 10 2020 Light winds will prevail, generally less than 20 knots through Wednesday. Attention then turns to a surface trough progged to track across the Great Lakes, the exact track remains uncertain at this time. Ahead of the trough, south winds should increase to 20-25 knots Wednesday night/Thursday. Behind this low, west to northwest gales should overspread the lake as the low deepens over Ontario/Quebec on Friday. Could be northwest gales up to 45 knots on Friday as this low strengthens over Quebec. This would be the strongest winds expected during the forecast. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...lg AVIATION...Rolfson MARINE...JLB
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Wednesday) Issued at 342 PM CDT Tue Mar 10 2020 The center of a surface ridge is located over Missouri this afternoon, and low pressure has been strengthening in southeastern Colorado. Water vapor imagery this afternoon shows a trough from North Dakota into Wyoming and a large cutoff low spinning well off the coast of California. A layer of stratus clouds held tight in our sky today, which limited warming into the afternoon. Surface dewpoints slowly increased through the day in central and eastern Kansas ahead of the surface low. That system will work its way across Oklahoma tonight while the upper trough noted on water vapor works toward the western Great Lakes region. Ascent ahead of the wave will combine with increasing moisture to produce rain/storms tonight. The better dynamics for thunderstorms looks to remain just south of the CWA where RAP soundings show a couple hundred Joules of elevated CAPE developing by 06Z. Closer to home, light rain is possible tonight, mainly south of Interstate 70. This system will quickly scoot east, so rain should clear by early in the morning. Patchy fog/low stratus is looking possible again early tomorrow, especially if clouds can clear a bit behind the departing system. If fog/stratus does develop, temperatures will be a little slower to warm than currently forecast. However, sunshine is expected tomorrow afternoon with temperatures expected to warm nicely into the 60s...again dependent on morning cloud cover. .LONG TERM...(Wednesday night through Tuesday) Issued at 342 PM CDT Tue Mar 10 2020 On and off chances for precipitation accompany our long-range forecast period. Dry weather midweek will be brief as POPs increase ahead of an approaching cold front on Thursday morning. Low level moisture will increase ahead of the front but overall ascent looks fairly limited. Thus, light rain is expected with QPF around a tenth of an inch. Thursday`s system also looks to move through the area fairly quickly so rain chances are limited to mainly the morning hours. Gusty northwest winds will develop behind the front Thursday afternoon, ushering in a cooler and drier airmass from the northern Rockies. High pressure will take control on Friday, allowing for a dry but somewhat cool day. The large upper closed low over the Pacific will finally advect northeastward over the southwestern CONUS late this week and become a weaker open wave. Large scale ascent ahead of the wave is noted in models which also show a large area of precipitation developing over the region. As such, POPs increase quickly Friday night into Saturday. With some cooler air still in place, light snow is looking possible early Saturday, transitioning back to rain during the afternoon. An active pattern looks to continue into early next week with more opportunities for rain/snow. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 638 PM CDT Tue Mar 10 2020 VFR conditions are expected to continue through 10Z with some mvfr cigs and vsbys possible, especially at MHK. Amount of clearing will be key with system moving through and clearing behind it. Expect some vcsh at MHK after 06Z til about 10Z. Confidence was to low to include vcsh at TOP and FOE at this time. If skies clear than some mvfr to ifr vsbys may be possible from 11Z-14Z. VFR expected with light winds after 15Z. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Teefey LONG TERM...Teefey AVIATION...53
Area Forecast Discussion
National Weather Service Las Vegas NV
750 PM PDT Tue Mar 10 2020 .SYNOPSIS...A Flash Flood remain in effect effect for parts of San Bernardino and all of Inyo County with particular concern across the southern Owens Valley, Death Valley, and perhaps the Taboose Burn Scar this evening as the heaviest rain is expected. A brief lull is expected Wednesday afternoon and night before another round of heavy rainfall returns to the forecast Thursday into Friday. This second area of heavy rain looks to be focused across eastern San Bernardino and southern Mohave Counties. This active pattern is expected to continue even into next week as yet another low pressure system looks to impact the region. && .UPDATE...Scattered light to moderate rain has redeveloped over much of southern Inyo, San Bernardino, Clark and Mohave Counties this evening with most of widespread moderate to heavy rain east of the area affecting portions of Arizona. However, showers are starting to enhance over southern Inyo which are expected to increase and move north across the county. This could have impacts on mainly the Georges and Taboose Fire burn scars with the potential of debris flows and rock slides. The current FF watch for those areas remains in place and will not make any changes. There could be some isolated thunderstorms overnight, but latest guidance actually shows less instability than previous runs. However, thunderstorm chances are expected to increase Wednesday late morning and afternoon with some isolated areas of heavy rain. No updates at this time, but rainfall amounts may be less than expected overnight. && PREV DISCUSSION 225 PM PDT Tue Mar 10 2020 .DISCUSSION...Through and Wednesday night. The widespread area of light to moderate rain that moved in overnight did dissipate as it moved north of Las Vegas as hi-res models suggested. Light rain showers have been isolated more than scattered so far this afternoon under cloudy skies. There have been some breaks in the overcast southwest of Las Vegas, not so sure we will reach the low 60s this afternoon. Visible imagery starting to show scattered thunderstorms developing east of the upper low from central California southeast to San Diego. Model output remains consistent that showers and thunderstorms associated dynamics within northeast quadrant of upper low and decreasing instability will expand in coverage across northwest San Bernardino and Inyo Counties this evening. This area will shift eastward into Clark County/eastern San Bernardino County late this evening and overnight. No change made to the Flash Flood Watch as expecting higher rain rates within Inyo County, more specifically Death Valley NP. Those higher rain rates may pose a threat and bring minor flooding to southern Nye, Clark and eastern San Bernardino Counties early Wednesday morning. Any impacts from snowfall will be above 8500 feet with 3-5 inches possible in upper Lee Canyon and Whitney Portal. 1-3 inches possible in upper Bishop Creek. Similar to today, showers and thunderstorms will become more isolated Wednesday afternoon and night. Thursday-Friday...The upper low is progged to finally move into southern California and eject east into Arizona Friday. This will be another period of active weather, specifically for San Bernardino, Mohave and Clark Counties. Dynamics become very impressive within the lower Colorado River Valley Thursday afternoon with that energy pivoting northward into our area Thursday night. On our latest coordination call with WPC there was no change made to the current Excessive Rain Outlook. Based on GFS and EC ensemble QPF output, specifically for Needles, Lake Havasu and Kingman confidence has been increasing in this second round of heavy rain. A Flash Flood Watch will probably be needed for southern Mohave County and eastern San Bernardino County, including Morongo Basin late Thursday afternoon into Friday. Saturday and Beyond...As this low finally gets out of the southwest Saturday models continue to advertise the next colder low slowly approaching from the northwest. Positioning of the trough over the weekend will lead to increasing southwest winds with some light showers still lingering over parts of the area. Precipitation chances increase the first half of next week as the trough moves overhead. Again, the system is colder so will be expecting some snowfall at lower elevations. && .HYDROLOGY...regarding the Taboose Burn Scar. A Flash Flood Watch remains in effect through late tonight. Latest guidance continues to show the burn area getting at a minimum light rain, and at a maximum briefly heavy rain this evening. The HRRR debris flow tool shows up to a half inch rainfall rates at this time, but only briefly between 7 pm and 10 pm this evening. This wouldn`t quite be enough for significant debris flows most likely, but could result in some minor issues on the creeks. However, continued close attention will continue this evening as these rain rates could overachieve and result in more significant impacts. && .AVIATION...For McCarran...Moderate confidence in forecast details this afternoon through Wednesday morning as a weather system brings several rounds of rain with low CIGs and possibly reduced VSBYs to the area. Light rain occasionally at or near the airport will remain through the remainder of the afternoon with CIGS around 3-3.5k feet, but occasionally dropping to around 2k feet at times. It`s possible that CIGS could raise to around 4-5k feet late this afternoon, but confidence is low in that occurring. Rain is likely tonight. Showers should become more numerous after 00Z and eventually become an area of rain pushing in from the south. Low confidence in current timing of more impactful rain, though chances increase quickly after 06Z. Between 06Z-12Z, rain may be heavy enough to reduce visibility and low status to 1000ft. Moderate confidence that ceilings drop to 3000-5000ft and remain there through Wednesday morning. After 12Z, rain may lighten/become more scattered in nature. Continued with this trend, however it is possible that the heavy to moderate rain and low ceilings will continue through 15Z or 18Z Wednesday. For the rest of southern Nevada, northwest Arizona and southeast California...A weather system will continue to push into southern California northeastward into southern Nevada through tonight, bringing with it widespread aviation impacts. Rain showers near DAG will continue at times through the day until more substantial rain moves in after 00Z. This rain shield will continue to push north and west, with it bringing at least MVFR CIGs, with potentially IFR ceilings and reduced visibility at times. Slight chance of precipitation ahead of the bigger push this afternoon, however it should be lighter precipitation and isolated to scattered in nature. Rain tonight may be heavy at times across all the TAF sites. Low confidence in the details of the forecast, including rain timing and when/how low ceilings will lower. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ UPDATE...Gorelow DISCUSSION...Pierce AVIATION...Gorelow For more forecast information...see us on our webpage: or follow us on Facebook and Twitter