Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/18/19

Area Forecast Discussion
National Weather Service State College PA
1150 PM EDT Sun Mar 17 2019 .SYNOPSIS... A weak area of low pressure will pass south of the state tonight. It may produce a light coating of snow along the MD border. Dry and mainly colder than normal temperatures are expected for Mon- Tues. But, some light snow or rain is possible Wednesday or Thursday and temperatures will be close to normals. A slight cool down is expected for week`s end. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Altocu/AltoStratus deck spreading in from the west this evening across the southwest half of the CWA, while skies will remain generally clear across the North-Central Mtns through 05Z and far eastern zones through about 03Z. Entrance region of a zonal upper level jet (110-115 KTS) along the Mason-Dixon line, will support a very weak area of low pressure at the SFC that will move just south of PA late tonight/early Monday. Expect some very light snow to brush our southern tier counties between 04Z-12Z Monday. Latest HREF and RAP indicate that this forecast may even be too robust on the snow, as both models indicate only spotty QPF of a few hundredths of an inch south of the PA/MD border. This forecast and slight southward trend to the precip is reasonable based on very dry air in place across all of Central PA, and the observation that the northern extent of any light snow across Ohio this evening is situated to the south of the mean 850-700 mb 285K Theta-E contour (which resides south of the PA turnpike) with near neutral to slightly positive Theta-E advection forecast in this layer overnight across the southwest half of our CWA. Places most likely to get a light dusting (less than an inch) would be folks right along the MD border in Somerset County, and mainly across the highest elevations. The temps in the cloud layer are ripe for big dendrites, but it is very dry underneath the 4-5kft cloud bottoms. A few flurries are still possible as far north as I-80 in Central PA and the Susq Valley, and also across the NW mtns, as a separate sfc and upper level trough drops SE from the Glakes and shifts the mean LLVL wind to the NW. No accums are expected north of a JST-AOO-THV-LNS line. Mins should be well below normals, with dewpoints only in the single digits across much of the northern half of the area. The srn half of the area will be closer to normal, with m-u20s there, mainly thanks to the lower/thicker clouds. Wind goes light/calm with a small nose of high pressure pretty much overhead tonight. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... The effects of the fast moving wave should pretty much be over by morning, but some flurries/sprinkles could linger into mid- aftn over the far SE, and some flurries are never out of the question in the Laurels. Northwesterly flow aloft will continue with temperatures holding around 10 degrees below normal. Sfc wind will be light in the morning, but pick up out of the NW through the day over the Alleghenies as slightly cooler air aloft slides over the area during the day. The cold advection will also lead to an increase in low clouds and some flurries/sprinkles across the north. There is just a small chc of an accum over the nrn mtns in the aftn. However, daylight hours in mid-March are a very difficult time to accum snow. Thus, PoPs will remain 30pct or less. Mon night looks like we should clear out over most of the area, but strato cu may linger over the NErn mtns. Mins a carbon copy of tonight. && .LONG TERM /TUESDAY THROUGH SUNDAY/... Surface high pressure will move across Tuesday and Tuesday night. Long-wave trough aloft will aid keeping temperatures about 5 degrees below normal for this time of year and help generate some afternoon clouds across the north. Surface high center moves off the coast Wednesday. Southerly flow ahead of next system along with March sun will warm temps to near normal. Next system will move in Wednesday night with good chance for rain and snow...snow mountains and colder locations north. Thursday a short-wave rotates around upr level trough bringing a chance for scattered light showers. Drier and warmer conditions heading into and through the weekend. Near normal highs and lows on Friday and Saturday with about a 10 degree jump on Sunday climbing into the 60s many areas through central PA and across the south. Warmer trend looks to last into the 8-14 day period. Spring officially begins at 5:58PM on Wednesday 3/20. && .AVIATION /04Z MONDAY THROUGH FRIDAY/... Main focus in the near term forecast will be on low pressure and associated light snow approaching from the Ohio Valley. All model data keep the snow along and south of the Mason Dixon Line late tonight and early Monday, with vfr conditions very likely at the southern Pa airfields and nearly certain elsewhere. High pressure building in from the Grt Lks should ensure widespread VFR conditions and light winds Monday afternoon and evening across all of central Pa. .Outlook... Tue-Wed...No sig wx expected. Thu...AM low cigs possible W Mtns. Fri...AM low cigs/snow showers possible W Mtns. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Dangelo/Lambert NEAR TERM...Dangelo/Lambert SHORT TERM...Dangelo LONG TERM...Watson/Steinbugl AVIATION...Fitzgerald
National Weather Service Eureka CA
221 PM PDT Sun Mar 17 2019 .SYNOPSIS...High pressure will aid in warm dry conditions across the region through Monday. Wet and unsettled weather is expected from Tuesday afternoon through late week. && .DISCUSSION...Visible satellite imagery shows Sunday morning marine stratus burning off along the coast during Sunday afternoon. The stratus has inhibited strong heating immediately inland from the ocean. However, abundant sunshine across the interior has aided in afternoon highs in the 60s and 70s. Another warm day appears on tap for Monday...though uncertainty in highs exists for coastal areas due to possible redevelopment of stratus tonight that may linger through part of the day tomorrow. Otherwise, an upper trough and associated weak surface frontal boundary will enter the area during Tuesday afternoon and evening. Light showers will become probable, with rain lingering through Wednesday night. A brief period of post-trough drying will be possible Thursday afternoon before another storm system approaches from the west Thursday night into Friday. Model guidance indicates rainfall will be slightly heavier with the Friday system...though hydrologic impacts are expected to be minor to non-existent at this time. After Friday, slightly cooler temperatures and snow levels falling to near 3500 feet are forecast to spread across the region during the weekend. JMG && .AVIATION...Areas of stratus and fog have been lingering along the immediate shoreline this afternoon. Shallow marine layer conditions may continue to erode this evening, primarily north of Cape Mendo where the marine inversion has been descending according to the ACV profiler. NAM profiles indicate drier boundary layer conditions this evening and tonight, while the HRRR was not quite as dry. Also, visible satellite imagery showed an eddy spinning up in the stratus field south of Cape Mendocino. Southerly winds right along the coastline may draw some of this stratus northward into KACV later tonight. Forecast confidence that VFR conditions this afternoon will be replaced with persistent IFR or LIFR conditions at KACV and KCEC for tonight remains low. Fortunately for KUKI, the forecast is much more simple with VFR holding through the forecast period. && .MARINE...Winds Monday will gradually switch to the south, and will increase to around 15 or 20 kt during the day Tuesday. This will likely generate some modest steeper seas in addition to the arrival of yet another westerly swell, resulting in combined seas that may top out in the 10 to 12 ft range, particularly across the southern and outer waters where winds will be slightly stronger. Winds will weaken Wednesday and Thursday, but yet another reinforcing swell will move through the waters Thursday, followed by a round of stronger southerlies Friday. As a result, seas Friday are likely to become a bit more hazardous, perhaps with combined wave heights in the 12 to 15 ft range. /BRC && .BEACH HAZARDS...A westerly long period swell will aid in a sneaker wave threat along area beaches through this evening. Beach-goers should use caution and keep a safe distance from the surf zone, as waves may suddenly wash much farther up the beach than expected after several minutes of relatively smaller waves. Remember that appearances can be deceiving, particularly in situations like this when the ocean surface appears relatively smooth and free of messier wind waves. /BRC && .EKA WATCHES/WARNINGS/ADVISORIES... CA...Beach Hazards Statement until 9 PM PDT this evening for CAZ101-103-104-109. NORTHWEST CALIFORNIA COASTAL WATERS...None. && $$ 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 Hastings NE
659 PM CDT Sun Mar 17 2019 .SHORT TERM...(This evening through Monday) Issued at 209 PM CDT Sun Mar 17 2019 A weak upper level disturbance and associated cool front across the Dakotas is expected to drop south across the local area tonight...with the last few runs of the HRRR and RAP trying to generate some light shower activity with its passage during the evening hours. With the focus of this disturbance to our east...felt that confidence of any appreciable precipitation locally was low...and decided only instead to increase cloud cover along with some silent pops through the evening hours. the surface...expect a ridge of high pressure to slide south across the local area overnight through Monday afternoon behind the aforementioned front...providing a slightly cooler airmass and light winds through tomorrow afternoon. At the same time...expect cloud cover to begin to increase from the northwest ahead of the next disturbance tomorrow...with a very small chance of some light rainfall west of highway 183 late in the day. .LONG TERM...(Monday night through Sunday) Issued at 209 PM CDT Sun Mar 17 2019 An upper level disturbance visible in settle in across the northern Rockies this afternoon will cross the local area Monday night through Tuesday...bringing the next potential round of precipitation to much of the local area. While moisture is not particularly robust with this system...any precipitation is unwelcome for most folks across our forecast area at this time. That said...models have trended...and continue to trend a bit further north and wetter with this system for the Monday night/Tuesday time frame...and precipitation totals have correspondingly increased about a tenth of an inch across the heart of the local area. At the same time...temperatures behind tonights cold front have come down a couple of degrees...and the chance for some accumulating snow has increased. While the snow will not stick around long...a band of snow is progged to set up across south central Nebraska overnight Monday into early Tuesday morning...potentially dropping from 1 to 3 inches of wet, slushy accumulation. upper level ridge will transition across the plains for the middle portion of the week, but a change in the pattern appears to be in store for late week as the first of several disturbances brings a chance of precipitation as early as Thursday afternoon...with off and on chances for additional precipitation through at least next Sunday, and possibly beyond. At this time, did not add thunderstorms to the forecast for the time being, but instability does increase across the region Saturday, which looks like the best chance for thunder across the local area in the current forecast period. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Monday) Issued at 652 PM CDT Sun Mar 17 2019 Light west wind should eventually turn more north as some mid- level sky cover approaches as a surface high moves in, keeping wind speeds on the light side. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ SHORT TERM...Rossi LONG TERM...Rossi AVIATION...Heinlein
Area Forecast Discussion
National Weather Service Jacksonville FL
954 PM EDT Sun Mar 17 2019 .UPDATE...A surface wave well offshore will move slowly east tonight allowing for cooler and drier air to gradually move into the area. 00Z HRRR suggests clouds will gradually lift most areas overnite but lower clouds persisting across the far southern counties. A few showers will also be possible there as well. Temps appear on track with lows in the 40s most areas except 50s along the Ne Fl coast. && .AVIATION...Prevailing VFR cigs tonight for most terminals. Lingering MVFR cigs at GNV til around 03Z and at SGJ til around 07Z. && .MARINE...Surface wave well offshore will slowly move east tonight. The gradient between the wave and high pressure to the northwest will produce exercise caution across all of the waters. Rip Currents: A high risk is anticipated for the Ne Fl beaches and a moderate risk for the Se Ga beaches on Monday. && .PRELIMINARY POINT TEMPS/POPS... AMG 41 67 44 63 / 0 0 0 0 SSI 47 67 51 60 / 0 10 0 0 JAX 47 69 51 64 / 0 10 0 10 SGJ 53 66 54 64 / 20 10 0 20 GNV 46 70 49 66 / 20 10 0 10 OCF 50 70 50 68 / 30 10 10 30 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$ PP/KB
Area Forecast Discussion
National Weather Service Key West FL
1042 PM EDT Sun Mar 17 2019 .SHORT TERM...(Tonight through Tuesday) A period of rain (sometimes heavy) and wind is coming up, with the worst weather coming from late Monday night through Tuesday. A shallow cold front is currently making its way down the southern Florida Peninsula, with surface obs showing it along a line from near Naples to Palm Beach. The front will continue to ease south tonight, passing south through the Keys before sunrise on Monday. It should be accompanied by little or no rain, but low clouds may fill in behind the front and set up an uncharacteristically gray start to Monday morning. The front will turn up stationary near the north coast of Cuba on Monday afternoon. Meanwhile, a distinct subtropical jet stream across northern Mexico and the Gulf will scoot the well-formed shortwave now making its way across the northwest Mexican state of Sonora into the western Gulf of Mexico on Monday night and Tuesday morning. As it moves east across the Gulf, its forcing will really energize the front to our south. Low pressure will first develop along the portion of the front west of the Yucatan on Monday, with the low pressure wave moving by along the front just to our south on Tuesday PM. Here on the north side of the front, this will bring windy northeast winds. Looking for lots of warm advection lift up and over the shallow cool dome, given strong southwest flow aloft. Favorable dynamics and lift will maximize on Tue afternoon as the favored left-exit region of the subtropical jet passes near the Keys, concurrent with the favored right-entrance region of a departing jet streak off the Carolina coast. With all of this lift acting on a juicy air mass with integrated Precipitable Water values of 1.75"-2.00", will be looking at heavy rain potential of 1"-1.5" over the Keys on Monday, with a slight chance of rain exceeding 2" over the Upper Keys. && .LONG TERM...(Tuesday night through Sunday) From Previous Discussion: The mid-upper level trough axis will slide east of the Keys Tuesday night. Rain chances will decrease sharply, followed by a welcomed few days of cooler than normal temperatures. Model guidance remains mixed for rain chances through the extended. We have therefore used a blend, which has consequently raised chances to 20% for much of the extended. No other changes at this time. && .MARINE... A cold front will slip into the coastal waters of the Florida Keys late tonight. Light and gentle northerly breezes will turn to the northeast and gradually freshen late tonight and Monday as the front stalls out near the northern Cuban coastline. Fresh to strong northeast breezes are expected Monday night through Tuesday night, as low pressure moves eastward along the stalled front. Northeast breezes will peak Tuesday evening. Northeast breezes will slacken somewhat Wednesday and Wednesday night. && .AVIATION... Surface winds will veer more northeasterly overnight at EYW and MTH. Around 09z-10z on Monday morning, the HRRR shows a small surge in NE wind as a cold front reaches the terminals. This should be followed by some low clouds with bases of 010-015 off the Florida Peninsula behind the front. BKN cigs that low may last for only a couple hours, if they develop at all. However, model time- height sections shows rich boundary layer moisture continuing until well into Monday afternoon, so at least SCT coverage of clouds below 020 will continue at times, with cigs at or below 030 being advertised in statistical guidance through Monday evening and beyond. && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...Haner Aviation/Nowcasts....Haner Data Collection......DR Visit us on the web at Follow us on Facebook and Twitter at:
Area Forecast Discussion
National Weather Service San Diego CA
223 PM PDT Sun Mar 17 2019 .SYNOPSIS... Temperatures will remain above average under mostly clear skies through Monday ahead of a Pacific storm system arriving midweek. Patchy low clouds and fog may return as early as Monday morning along the coast, though more likely Tuesday morning as a coastal eddy develops. Conditions will cool as onshore winds increase this week. Scattered showers are expected Tuesday night through Thursday with the best chance on Wednesday. A few thunderstorms are even possible Wednesday through Thursday as colder air aloft moves in from the north. A weak upper ridge will build in briefly on Friday ahead of another system passing to the north this weekend, but the tail end could affect Southern California for the potential of additional showers, mainly on Saturday. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... GOES-17 Satellite imagery shows a clear sky across the region. No signs of any low clouds developing. WRF is showing a coastal eddy developing overnight with fog or low clouds moving in along the coast, but this model is often a day too soon. HRRR surface visibility is above 10 miles overnight. So while patchy fog or low clouds is possible, it is of low confidence. Believe most of the area will be clear tonight through Monday. Monday night stands a better chance of fog or low clouds near the coast. Temperatures have really warmed up today with widespread 70s and even low-mid 80s inland. The immediate coast is in the 60s as a sea breeze has developed and blowing in colder air off the 57 degree ocean temps. Today is the peak of the warmth. Conditions will gradually cool over the next few days as onshore flow takes hold. The next Pacific system is poised to arrive by Tuesday night and move across the area Wednesday-Thursday. Strength of this system is in question. The operational GFS and GFS ensemble mean continues with higher heights compared to the ECMWF, which digs the closed low further south and overhead by Thursday. Given this and uncertainties with this, followed a blended approach. As colder air moves in overhead Wed-Thu, instability will increase to allow for the potential of isolated thunderstorms to develop. Added this into the forecast. Precipitation amounts continue to look to be rather tame as the transport of moisture with this system is in a diminishing process as the moist plume moves over the area. Still, it is looking like 0.25-0.50" will fall at most locales west of the mountains, 0.50-1.00" along the coastal mountain slopes to 0.05-0.15" over the deserts. Maximum hourly rates to 0.50"/hr is forecast in isolated heavier showers or tstorms that develop. Snow levels looks to be at near 6000 FT on Wednesday then down to about 5500 FT on Thursday. Snowfall amount of 2-4" are possible at ski resort level with heavier snow of 6"+ above 8000 FT. Southwest winds will become strong along the deserts slopes Tuesday night-Wednesday with gusts to 50+ mph possible. The system will move away from the area Thursday night with weak upper ridging building in on Friday. However, GFS ensembles show the southern extent of another storm system affecting SoCal this weekend, right now with a Saturday timing. This looks to bring some more showers to the area with low precipitation amounts expected as this looks weaker. That system moves away Sunday with tranquil weather following in its wake next Mon-Tue. GEFS shows lowering heights associated with yet another shortwave/storm system moving in from the west and into SoCal Wed-Thu, March 27-28. An active weather pattern lies ahead. && .AVIATION... 172005Z...As luck would have it, we will see mostly clear skies with unrestricted vis through early this evening. Small chance of low clouds with bases 700-1000 ft MSL developing along the coast after 08Z Monday, with low to moderate confidence. SCT cigs near 1000 ft MSL forecasted to continue for much of Monday morning for coastal TAF sites. Inland areas will see mostly fair skies throughout the day. && .MARINE... No hazardous marine weather is expected through Tuesday night. A Pacific storm may bring periods of showers, building seas, and gusty west winds Wednesday through early Friday. && .BEACHES... High surf of 6-9 ft in portions of San Diego County possible Wednesday through Thursday due to a building west swell of 7-9 ft at 15-17 sec from 280 degrees. Elevated surf of 3-6 ft is possible in Orange County. High rip current risk will occur Wednesday through Thursday. Swell and surf will subside on Friday. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && $$ PUBLIC...Gregoria AVIATION/MARINE...APR