Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/29/18


Area Forecast Discussion
National Weather Service Albany NY
1041 PM EDT Sat Apr 28 2018 .SYNOPSIS... An approaching cold front will bring some showers and thunderstorms to the region through this evening, with locally gusty winds possible. Behind this frontal boundary, colder air will work back into the area for the rest of the weekend, with some additional lingering rain and mountain snow showers for Sunday into Sunday night. Although the week will start off cool with a few additional showers on Monday, much milder conditions are expected through the remainder of the week. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... Updated at 1030 PM EDT... The cold front has now moved east of the entire forecast area with winds shifting to northwest as far east the Connecticut River Valley. The steadiest band of rain continues behind the front over the Berkshires down through the Taconics east of the mid-Hudson valley, however there has been a sharp eastern edge with little to no rain getting to eastern Litchield county so far. We expect gradual eastward progress with the eastern edge of this rain area overnight, meanwhile another wave of showers is expected to move north from eastern Pa across eastern NY late tonight bringing another round of rain toward daybreak to the mid and upper Hudson River Valley. Temperatures will slowly fall into and through the 40s, with some 30s over higher terrain west of the Hudson Valley by daybreak. Updated at 830 PM EDT... Cold front is moving slowly east and has moved east of the mid and upper Hudson Valley as of 830 pm. A band of moderate rain has developed along and behind the front. Convection along the leading edge of the this afternoon has diminished with the loss of heating and modest instability that was in place earlier today. Strong upper low will move east across upstate NY overnight. The front will slow down over New England later tonight with bands of showers continuing to move north along and behind the slowing frontal zone. Details from the latest HRRR and 18z NAM nest show that the rain may diminish for awhile from late evening into the early morning hours from the Hudson Valley west, however showers will increase across that area after about 2 am as another wave of rain moves north along and behind the front. Meanwhile east of the Hudson Valley rain will continue for much of the night. Temperatures will be falling behind the front wih most areas settling into the upper 30s to mid 40s by daybreak Sunday. As of 408 PM EDT...Slow moving surface cold front is moving across central New York and heading towards the area. MRMS imagery shows several broken bands of showers and embedded thunderstorms expanding into eastern New York. Some showers/storms have already produced pea sized hail and brief downpours across the area. A more concentrated line of thunderstorms is located south of the region over eastern PA. Ahead of the front, diurnal heating has allowed temps to reach into the 60s over much of the area, although dewpoints remain in the 40s. 3km HRRR and NAM suggest showers and embedded thunderstorms will continue to expand eastward across the rest of the area into the evening hours. Instability values are fairly meager this afternoon due to low EL around 500 mb and fairly dry surface dew points. 12z HREF mean values of surface and MU CAPE values are around 250-500 J/kg for much of the area through this evening and SPC mesoanalysis is showing similar values so far this afternoon. However, low and mid level lapse rates are fairly steep and 0-3 KM bulk shear values are around 40 kts, so totally cannot rule out some gusty winds within any shower or thunderstorm, especially considering the inverted-v sounding in place. SPC has placed parts of the Catskills in a marginal risk for severe weather, mainly due to this threat of locally gusty winds, which makes sense considering the latest 3km HRRR/NAM reflectivity output and the heavier line of showers/storms just to our south. The threat for thunder should wane quickly after sunset, as instability lowers with the loss of heating. Behind the cold front this evening, some additional showers will linger into the overnight hours, especially for northern and high terrain areas, as low pressure slowly tracks through the St. Lawrence Valley and the large closed off upper level low approaches from the Great Lakes. Temps should start to fall out behind the front, and by late tonight, some wet snow may even start to mix in with the rain showers across the western Adirondacks. Lows look to fall into the mid 30s to mid 40s across the area. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... The large closed off upper level low will track across upstate New York on Sunday and linger across New England for Sunday night into Monday. With the cyclonic flow in place, some additional showers look to occur for Sunday into Monday, especially for northern and high terrain areas. Best timing for most concentrated areas of showers looks to be Sunday afternoon through late Sunday evening, and then again of the backside of the upper level low for Monday morning. With the core of the upper level low over the area, 850 hpa temps will fall to -2 to -5 C. For most of the area, the boundary layer will be too warm for any snowfall, but high terrain areas may see some wet snow mixing in and parts of western Adirondacks and southern Greens may even see a light accumulation across the highest elevations. High Temps on Sunday look to generally be in the 40s to low 50s across the area, although some upper 30s will occur across the Adirondacks. Lows on Sunday night look to fall into the 30s everywhere. Highs on Monday will be in the mid 40s to mid 50s. As the upper level low starts moving away, the threat for showers should be diminishing by Monday night and it will finally start to clear out. Lows will be in the 30s once again. && .LONG TERM /TUESDAY THROUGH SATURDAY/... A progression of dry to showery weather is in store...with temperatures averaging above normal. High pressure sliding off the southeast coast on Tuesday will bring increasing moisture and clouds into our area as the week progresses. Things will start out dry...becoming downright warm by mid-week. Only showers moving into the area on Thursday will serve to cool the lower atmosphere in any way before the passage of a cold front from the northwest at the end of the week. A rumble of thunder is not out of the picture on Thursday, but instability is expected to be limited. High temperatures will be in the upper 50s to lower 70s range on Tuesday, the upper 60s to lower 80s on Wednesday. Thursday will be similar to Wednesday, with slightly cooler temperatures noted for Friday. Saturday will be a very pleasant and generally dry day, with highs from around 50 degrees in the Adirondack high peaks...to near 70 in the lower Mid-Hudson Valley. Normal early May highs in Albany are in the mid 60s, with the normal lows in the mid 40s. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... Cold front has moved east of the Hudson Valley as of 730 pm and will be east of PSF by around 900 pm. Showers will continue along and behind the front through tonight and lingering into the day on Sunday. Conditions will be mainly VFR through this evening but there will be periods of MVFR cigs and vsbys in showers. Cigs will lower to mostly MVFR later tonight through Sunday morning, then improve slightly with areas of VFR by Sunday afternoon. Winds will be west- northwest, with some brief higher gusts at POU and PSF this evening with the frontal passage, otherwise west-northwest winds can be expected tonight through Sunday with speeds averaging less than 10 kts. Sunday Night: Moderate Operational Impact. Chance of SHRA. Monday: Moderate Operational Impact. Chance of SHRA. Monday Night: Low Operational Impact. Slight Chance of SHRA. Tuesday: No Operational Impact. NO SIG WX. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: No Operational Impact. NO SIG WX. && .FIRE WEATHER... A cold front will pass through this evening with some showers and thunderstorms. With an upper level disturbance over the area, some additional rain and mountain snow showers will occur for tonight through Monday. Most areas look to see a wetting rainfall from this precipitation. Through the remainder of the weekend and into Monday, RH values will stay elevated, generally above 50 percent. West winds tomorrow will be 10 to 20 mph and remaining west for Monday at 5 to 10 mph. && .HYDROLOGY... Some showers and thunderstorms are expected through this evening with the passage of a cold front. Behind the front, some additional showers are expected to linger for Sunday into Monday, thanks to a large upper level disturbance moving over the area. The precip may changeover to snow showers for the highest terrain late in the weekend, but liquid equivalent amounts are expected to range from a quarter of an inch over far southern areas to nearly an inch over the Adirondacks. This precipitation will allow for some additional rises on rivers and streams but river levels are expected to remain below flood stage. A few rivers and reservoir levels in the Adirondacks where flows have been high due to recent rainfall and snowmelt may hover near action stage, but latest forecasts don`t anticipate flooding at this time. Dry weather is then expected for Tuesday into Wednesday with mild weather. River levels should continue to recede. Most of the hydrologic significant snowfall has already melted out of the Adirondacks, but any remaining snowpack should melt this 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...Frugis NEAR TERM...MSE/Frugis SHORT TERM...Frugis LONG TERM...ELH AVIATION...MSE/Speciale FIRE WEATHER...Frugis HYDROLOGY...Frugis
Area Forecast Discussion
National Weather Service Binghamton NY
953 PM EDT Sat Apr 28 2018 .SYNOPSIS... A cold trough of low pressure will provide unsettled conditions and chilly temperatures through the rest of the weekend and into Monday. Drier weather, with a significant warming trend, is anticipated next week. && .NEAR TERM /THROUGH SUNDAY/... Behind a cold front, northwest and northerly flow will result in snow showers developing overnight and likely continuing through Sunday and into Sunday night. Gusty winds expected on Sunday with temperatures in the 30s and lower 40s. Few changes were made with the late evening update overnight incorporating aspects of the latest mesoscale model guidance. A cold front has moved through our region this evening. Behind the front, Winds will shift to the nw and colder air will spread across the region. The broad large scale lift from the upper low will combine with CAA in the mid levels with steepening lapse rates, and allow the showers to persist tonight...but mainly keep most of the precip confined to central NY...with even a small amt of support from Lake Ontario possible. 850mb temperatures will drop into the -4 to -6 deg C range tonight, and allow the development of snow showers or a mix of rain and snow. Snow will likely have a hard time accumulating...but the higher elevations above 1500 ft may see a half to 1 inch of snow by mid Sunday morning. The cold air continues to filter in during the day Sunday with gusty nw winds making it feel even colder. Highs during the day will likely have a hard time getting much above 40. The cold air aloft and slightly unstable air mass is expected to continue to be supportive of snow showers or a mix of rain and snow through most of the day...but with much of the snow not accumulating during the daylight hours. We are starting to get into the range of the HRRR and RAP now. These models late this evening are indicating the showers to be fairly widespread so the pops were increased for most of the day Sunday. The low pressure system will track slowly ewd Sunday and remain an influence over much of the region into Sunday night. There is a gradual warming trend, but likely not warm enough during the overnight hours to change the snow to rain. So, will likely see scattered snow showers continue through the night with an additional half to 1 inch in the higher terrain once again. The area that has the best chance of seeing accumulating will be across the highs south of Syracuse and into the Catskills and srn Tug Hill. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... 220 PM update... Significant changes will occur this period, beginning with an abnormally cold trough sliding out of NY to give way to a warm trough building into the Ohio Valley and Great Lakes. A mix of rain and snow showers is forecast for early Monday. A few tenths of snow accumulation are expected over high elevations, before temperatures warm into the lower or middle- 50s during the afternoon. The ridge axis will cross Lake Erie on Tuesday. The GFS is forecasting a wave to rotate over the top of the ridge and cause a few showers over NY. We are sticking to a dry forecast at this point, as the other models disagree with the GFS assessment. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... A mild, spring-like pattern is forecast for the long term period. The ridge will flatten on Wednesday, while a weak cyclone will move across Southern Ontario Province. This system may set off a shower or thunderstorm Wednesday afternoon. Additional shower activity is possible on Thursday as a complex frontal system moves east toward the Great Lakes. A cyclone will form along the front over Michigan and track toward NY Thursday night, increasing the likelihood for rain. The storm system will pull a cold front across NY and PA on Friday. Temperatures will reach well into the 70s on Wednesday and Thursday, then drop several degrees behind the cold front Friday. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... A cool moist northwest flow will continue over the area through this TAF period with lowering ceilings early this evening. At KRME/KSYR/KITH/KBGM, ceilings will lower into the Alternate Required category shortly then to IFR between 04Z-06Z. At KELM/KAVP, ceilings will lower into the MVFR/Alternate Required category between 03Z-06Z. Conditions may slowly improve Sunday by 15Z to Alternate Required/MVFR conditions along with MVFR visibility restrictions in mixed rain/snow showers especially at KRME/KSYR/KITH. Northwest winds at 8-10 knots overnight increasing mid morning Sunday at 12 knots with gusts 18-22 knots. Outlook... Sunday night...MVFR/IFR restrictions possible from rain showers, and at times, snow showers. Monday through Wednesday...VFR. Thursday...Restrictions possible in showers and isolated thunderstorms. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && $$ SYNOPSIS...BJT NEAR TERM...BJT/MWG SHORT TERM...DJP LONG TERM...DJP AVIATION...RRM
Area Forecast Discussion
National Weather Service Bismarck ND
903 PM CDT Sat Apr 28 2018 .UPDATE... Issued at 900 PM CDT Sat Apr 28 2018 Red Flag Warning expires at 9 PM CDT as critical fire weather conditions have subsided. Also the wind advisory has also expired. While gusty winds will continue for a bit the strongest winds have abated. UPDATE Issued at 625 PM CDT Sat Apr 28 2018 Strongest surface winds following the h850 wind profile with HRRR soundings showing a decoupling around 02z/9 pm cdt. Winds will decrease a bit then but remain gusty through the evening. Current forecast looks ok. Wind advisory southwest and Red Flag Warnings continue through 9 pm cdt. && .SHORT TERM...(This evening through Sunday) Issued at 240 PM CDT Sat Apr 28 2018 Winds and critical fire weather conditions continue to highlight the short term period. Currently, upper level ridge axis stretches from south to north across the high plains east of the Rockies. Surface high pressure over the Upper Mississippi Valley and low pressure developing over the Northern Rockies has developed a tight pressure gradient across western and central North Dakota today. Gusty south/southeasterly winds developed in response over much of my area. Coupled with a dry boundary layer and lack of moisture advection, resultant mixing from these winds has seen decreasing humidity as the day progresses. Already reaching Red Flag criteria and this will only get worse as the afternoon progresses and more locations dry out. Lack of a good green-up/dry 1-hr fuels only exacerbating critical fire weather conditions today. Will see improving fire weather conditions early to mid evening as we decouple and the mixed layer lowers, resulting in winds decreasing. Will also have cooling temperatures seeing RH values increase. Breezy south/southeast winds re-increase a bit overnight as a very strong low level jet (LLJ) develops (40-55Kts) into the Northern Plains. Main impacts from the LLJ will be an increase in low level wind shear impacting aviation as the boundary layer remains parched until after 12Z Sunday. Upper ridge axis moves into the eastern Dakotas by sunrise Sunday morning. Surface trough moves into the western Dakotas Sunday afternoon as southwest flow aloft develops from the Rockies into the Plains. Increasing boundary layer moisture through the day with sfc dewpoint temperatures increasing well into the 40s to near 50F. Daytime highs still expected to range well into the 70s as 900MB temps increase from 7-12C today to 17-23C Sunday aft. All guidance keeps my area dry until Sunday night when the better large scale forcing arrives from the west as the upper level low moves into the Northern Rockies region. .LONG TERM...(Sunday night through Saturday) Issued at 240 PM CDT Sat Apr 28 2018 Thunderstorm potential Sunday night and perhaps Monday, and an early May cool down, highlight the extended forecast. See the fire weather discussion below for details regarding possible fire weather concerns for Sunday. SPC has maintained a marginal risk for severe thunderstorms across southwest North Dakota Sunday evening. The 12Z models continue to suggest convection initiating across southeast Montana and northern Wyoming, then propagating northeast into southwest North Dakota Sunday evening. This convection is expected to be sustained by steep mid level lapse rates and a strong mid level jet ahead of the upper low. Convection may be consolidated, and elevated, by the time it reaches North Dakota. Wind would seem to be the primary threat given the dry air with sfc Tds barely touching 50F. However, this could be limited by stabilization of the boundary layer. Marginal severe hail is also possible, but, a likely secondary threat. The thunderstorm threat will propagate into central North Dakota overnight. However, the severity is somewhat uncertain but should decrease with time. For Monday, thunderstorm potential and severity looks to reside more to our south and southeast. Have tempered thunder mention due to the latest guidance. Thereafter, models still suggest on average cooler/below normal temperatures for the start of May, highs in the upper 50s and lower 60s and lows dropping into the 30s, as the mean flow will be northwest. Possible ridging late next week may see the one or two days closer to average temperatures. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 625 PM CDT Sat Apr 28 2018 Strongest surface winds following the h850 wind profile with surface wind gusting to 30-35kts KDIK-KBIS til 02Z. Then forecast soundings show a decoupling around 02z resulting in a lower surface winds but a low level speed max over 50 kts around 1 thousand feet agl over west central North Dakota. VFR at all taf sites with wind shear to 50 KTS below 1 thousand agl KJMS- KBIS- KMOT- KDIK. && .FIRE WEATHER... Issued at 240 PM CDT Sat Apr 28 2018 Red Flag Warning remains in effect through early this evening for western and most of central North Dakota. Strong southeast winds have developed across the area today and will continue before winding down this evening. Peak gusts have ranged from 30 - 40 mph with sustained winds ranging from 20-25 for the most part. Relative humidity continues to fall, now in the low 20s to mid 30s, and will bottom out to near 20 percent if not a tad lower some locations in the mid/upper teens. Expect improving conditions between 7-9PM CDT this evening. For Sunday: gusty south/southeast winds will continue over south central and eastern parts of North Dakota. Sustained winds to 25 mph and gusts to 35-40 mph are forecast for these areas. However, increasing surface moisture tonight into tomorrow will see higher relative humidity values on Sunday, ranging from 30-40 percent. This will limit the fire weather threat but will be closely monitored. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA SHORT TERM...NH LONG TERM...NH AVIATION...WAA FIRE WEATHER...NH
Area Forecast Discussion
National Weather Service Wichita KS
1012 PM CDT Sat Apr 28 2018 .UPDATE... Issued at 1011 PM CDT Sat Apr 28 2018 Low level jet just beginning to slowly increase for areas west of I-135 at this time, with a gradual increase in low level moisture transport. Latest RAP model data suggests that moisture transport will be slow to increase into central KS overnight, with a general increase for areas over north central KS. So think any chance of showers or an isolated storm will be delayed. Rap shows moisture transport possibly increasing enough for a rogue storm or two north of I-70 across north central KS, after 09z, but confidence in this occurring is diminishing. Will keep a slight pop in for now, but think precip chances into early Sun morning look slim. Ketcham && .SHORT TERM...(This evening through Tuesday night) Issued at 253 PM CDT Sat Apr 28 2018 Water vapor imagery shows the upper low coming on shore over the Pacific NW with upper ridging about to move out of the Rockies and into the high Plains. At the surface, a cold front extends from northern AR into far sw KS. Models have remained consistent the last several days in lifting a piece of energy out of the Desert Southwest and into the central Plains late tonight into Sun morning. As this occurs, decent mid level theta-e advection sets up along and northeast of a tight mid level baroclinic zone. While it`s not out of the question to see some iso thunder with this activity over central KS, not expecting anything strong or severe. Return flow will start to get going on Sun as lee troughing continues to deepen with south winds expected to be even stronger on Mon. Will run with a wind advisory Sun afternoon for a few central KS counties with another wind advisory eventually needed Mon for a much larger area. One upper impulse will be lifting over western Nebraska on Mon night while a much more robust piece of energy will be approaching the southern CA coast. Strong return flow will keep strong moisture advection in place across the Plains and by Tue afternoon, a dryline will extend from west-central KS down into western OK. Meanwhile, a cold front will extend through eastern Nebraska into central KS. With lack of large scale forcing, will likely take an area of enhanced convergence along of the boundaries to get a storm to develop late Tue afternoon/Tue evening. At this time, feel the best surface convergence will be near the triple point over central KS. So while not expecting widespread severe storms Tue, can`t rule out a few storms. Will be plenty of instability and shear to get supercells along both the dryline and synoptic front. .LONG TERM...(Wednesday through Saturday) Issued at 253 PM CDT Sat Apr 28 2018 Stronger mid/upper flow will move out across the southern/central Plains for Wed as the main upper impulse slides over the Desert Southwest. Meanwhile, low level moisture will continue to pump into the region with mid 60 dewpoints a good bet by Wed afternoon. Once again, expecting a triple point to be located somewhere over west-central KS by Wed afternoon with the dryline extending into western OK. Currently expecting more widespread storms along the dryline/warm front Wed due to less capping, better large scale forcing and richer low level moisture. 0-6km shear will be in the 50 to 60kt range with CAPE in the 2500-3000J/kg range. Low level shear isn`t that impressive until surface flow starts to back closer to sunset as low level jet increases. Deep layer shear looks to be normal to the dryline which should keep anything that develops along it fairly isolated which should minimize storm interaction and increase tornado potential, especially toward evening. Also seems to be some model agreement now that much of eastern KS will be in play for severe storms Thu afternoon and evening as the front appears slower to push east. Of course, much of that will be dictated by how Wed evening storms modify the environment, but think it`s at least worth a mention at this point. So we could be looking at a 3 day severe weather event across the Plains. Cold front will push well south of the area for Fri and Sat as high pressure settles over the area. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 642 PM CDT Sat Apr 28 2018 VFR conditions are expected for the next 24 hours. HI-rez short range models suggests that there is a chance for some elevated SHRA/VCTS to develop across central KS early on Sun morning, during the 09-12z/Sun time frame. Will keep a VCTS going for this chance for the KRSL and KSLN taf sites. Could also see some low level wind shear for the central KS tafs overnight, as the low level jet increases. Ketcham && .FIRE WEATHER... Issued at 253 PM CDT Sat Apr 28 2018 Fire danger concerns will return to the area Sun and especially Mon. South winds will be on the increase for Sun and especially Mon. For Sun, we are looking at south/southeast winds sustained around 30 mph with gusts to 40 mph for areas generally west of I-135. For Mon, we should see widespread south winds in the 30-35 mph range with gusts 40-45 mph. This will elevate the grassland fire danger into the very high category for areas west of I-135 Sun afternoon and for most of the area Mon afternoon. Grasses starting to green up and higher RH values will keep the grassland fire danger from getting into the extreme category. && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 51 77 60 79 / 10 10 0 10 Hutchinson 50 77 60 80 / 10 10 0 10 Newton 49 76 59 78 / 10 20 0 0 ElDorado 49 76 59 78 / 10 10 0 0 Winfield-KWLD 51 77 59 79 / 10 0 0 10 Russell 50 80 61 84 / 30 10 10 10 Great Bend 51 81 60 82 / 20 10 10 10 Salina 50 79 61 83 / 20 30 10 10 McPherson 50 77 60 80 / 20 20 0 10 Coffeyville 48 75 57 79 / 10 0 0 0 Chanute 46 73 56 78 / 10 10 0 0 Iola 45 73 56 78 / 10 10 0 0 Parsons-KPPF 47 75 57 78 / 10 0 0 0 && .ICT WATCHES/WARNINGS/ADVISORIES... Wind Advisory from noon to 8 PM CDT Sunday for KSZ032-033-047- 048-050. && $$ UPDATE...Ketcham SHORT TERM...RBL LONG TERM...RBL AVIATION...Ketcham FIRE WEATHER...RBL
Area Forecast Discussion
National Weather Service San Francisco Bay Area
850 PM PDT Sat Apr 28 2018 .SYNOPSIS...Isolated light showers or sprinkles are possible through about midday Sunday, mainly in the North Bay. Otherwise, expect dry and continued cooler than normal weather through the middle of next week. High pressure will start to build midweek and beyond with a modest warming trend expected during the second half of next week. && .DISCUSSION...As of 8:50 PM PDT Saturday...An upper low moving inland over the Pacific Northwest and far northern California produced isolated light showers and sprinkles in the Bay Area today. Most locations only received a trace of precipitation, but a few locations managed to pick up a hundredth or two. Temperatures today remained slightly below normal in most locations. The 00Z NAM shows isolated light showers redeveloping in our area later tonight and into Sunday morning as the upper low begins to dig to the southeast and as a shortwave trough rotates to the southwest of the low and across our area. The latest HRRR model also indicates spotty light precipitation, mainly in Sonoma County. A forecast update was completed earlier this evening to add a slight chance of showers to the forecast for late tonight and Sunday morning, mainly in the North Bay, but also south along the SF Peninsula. If showers do develop in these areas, accumulation is expected to be very light and similar to what occurred today. Another upper low is forecast to drop in from the north late on Monday. Initially, from late Monday through most of Tuesday, the models agree that precipitation with this low will mostly be confined to our east over the Sierra Nevada. But then, as the low sinks to our southeast late Tuesday, both the 00Z NAM and 18Z GFS show a disturbance rotating to the northwest of the low and triggering showers across the southeastern portion of our area from late Tuesday into Tuesday night. Our forecast currently does not include shower chances then, but chances will likely be added to the forecast if the 00Z GFS and/or 00Z ECMWF show something similar to the 00Z NAM. These upper lows will maintain cooler than normal temperatures across our area through the middle of next week. Longer range models forecast an upper ridge to build across California during the second half of next week, resulting in dry and warmer weather. && .AVIATION...As of 4:50 PM PDT Saturday...Upper level low has brought SCT-BKN cloud decks to the SFO Bay Area and North Bay. A few showers were reported earlier but have moved out. More cigs have developed this afternoon but bases are high enough to maintain VFR conditions. The inversion will reform at a lower level after 05Z with areas of MVFR. Vicinity of KSFO...VFR with cigs at or above 3500 feet through 05Z. Lower deck of clouds form after 05Z with conditions becoming MVFR. SFO Bridge Approach...Similar to KSFO. Monterey Bay Terminals...Onshore flow will allow for MVFR cigs after 03Z in MRY slowly spreading to SNS by 09Z. && .MARINE...as of 5:20 PM PDT Saturday...Northwest winds will gradually increase over the next 24 hours throughout the coastal waters as a system drops from the Pacific Northwest. Moderate winds are forecast to continue into the early part of next week. These winds will produce fresh swell and steep waves. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm && $$ PUBLIC FORECAST: Dykema AVIATION: W Pi MARINE: W Pi Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/nwsbayarea www.twitter.com/nwsbayarea www.youtube.com/nwsbayarea
Area Forecast Discussion
National Weather Service Spokane WA
456 PM PDT Sat Apr 28 2018 .SYNOPSIS... Sunday through Tuesday will feature seasonal temperatures with occasional showers. The cool and unsettled weather will ease by midweek as a ridge rebuilds over the Inland Northwest with warmer and drier weather. && .DISCUSSION... Tonight through Monday: An upper-level low will slowly migrate through the region during this period. Smaller scale disturbances rotating around the low will delivering periods of showers with most activity tracking over the periphery of the Columbia Basin. Away from this features, afternoon heating will bring a threat for hit or miss light showers. There will be a small chance for thunderstorms across far southeastern WA and the lower ID Panhandle each of the next few afternoons/early evenings and into NE WA Sunday afternoon but instability parameters are marginal so not expecting much more than infrequent lightning strikes. HRRR is also indicating a few cell developing around the Waterville Plateau this evening so this is something that will be monitored through sunset. Precipitation amounts over the next few days will generally be light except on a highly localized basis under any convective cells. In general, less than a quarter of an inch is expected over the next 48 hours. Temperatures will remain on the cool, seasonal side with afternoon highs in the 50s to 60s and lows in the upper 30s to 40s. Rainfall from the last 24 hours will keep a small chance for patchy fog in the morning hours in and around the sheltered northern valleys. /sb Monday night through Tuesday night...By Monday night the upper low will be well away from the Pacific Northwest. Northwest- northerly flow and lingering moisture will keep a chance of rain showers and high elevation snow showers across the eastern third of the forecast area, east of a line from Republic to Ritzville. Precipitation amounts will be under a tenth of an inch in the north Panhandle and a few hundredths elsewhere. Temperatures will begin to warn through this period with high temperatures from the high 50s to around 70. Wednesday and Thursday...High pressure will build into the region for a warming and drying trend. Temperatures will warm 4-6 degrees on Wednesday and another 3-4 degrees Thursdays which will put the highs in the 60s to 70s. Friday and Saturday...Model guidance has been consistent showing the ridge flattening out Friday and Saturday with another weather system coming through the region on Sunday. The ECMWF on the other hand is about 24 hours quicker with the low. For now the forecast will lean in favor of the slower solution with the ridge flatting and the low pressure system coming in on Sunday. That will mean cooler temperatures, and an increasing chance for showers across the northern mountains on Friday and and just about all areas on Saturday. Tobin && .AVIATION... 00Z TAFS: Afternoon heating will keep the chance of showers for KCOE through sunset, while shower chances linger through 08 or 09Z for KLWX and KEAT. VFR conditions are expected at all TAF sites. There will be a chance for some early stratus at KGEG-KCOE given the wind direction and cool, moist boundary layer. Some weak disturbances will bring the chance for scattered afternoon showers again on Sunday for KPUW, KLWS, KCOE, and potentiall KGEG and KSFF. /bw && .PRELIMINARY POINT TEMPS/POPS... Spokane 41 59 41 58 41 60 / 10 10 10 30 10 20 Coeur d`Alene 42 58 39 57 39 58 / 10 10 20 40 20 20 Pullman 41 56 39 55 39 57 / 40 20 10 20 10 20 Lewiston 46 62 44 61 43 63 / 50 20 20 20 10 20 Colville 43 59 41 63 41 67 / 20 40 30 30 10 20 Sandpoint 41 57 38 55 39 56 / 30 20 40 40 20 30 Kellogg 39 56 37 53 37 54 / 20 30 20 40 30 40 Moses Lake 42 66 42 66 41 68 / 10 0 10 10 10 10 Wenatchee 44 62 43 64 42 67 / 10 10 10 10 10 10 Omak 44 61 42 65 42 67 / 20 10 20 10 10 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
Area Forecast Discussion
National Weather Service Mount Holly NJ
945 PM EDT Sat Apr 28 2018 .SYNOPSIS... A strong cold front will pass through our region this evening. Low pressure is forecast to meander in New England and vicinity on Sunday and Monday as high pressure slides from the Great Lakes to the Carolinas. The high is expected to settle over the western North Atlantic and it should influence our weather from Tuesday into Friday. Another cold front approaching from the northwest is forecast to arrive on Friday night. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... 930 pm update: Extended isolated thunder chances in the forecast for the next few hours given the continued flare-up of isolated storms near/southeast of I-95 and in portions of Delmarva. Cells continue to exhibit pulsing nature with small hail still possible (though quite isolated) where towers reach around/above 20 kft. Light rain is picking up to the west, so gradually increasing PoPs north of the Mason-Dixon Line for much of the night continues to make sense. 800 pm update: Line of low-topped showers and isolated storms is beginning to wane as nocturnal cooling commences. However, the storms were rather prolific producers of small hail, as virtually any storm with discernible radar echo tops to 20,000 feet was able to produce hail that reached the surface. Several reports of pea-sized hail (or even slightly larger) were received with a storm near Coatesville, PA, and with a line of storms affecting Sussex, Warren, Hunterdon, and Morris Counties between 5 pm and 7 pm. Have had to make several changes to the forecast to account for the evolution of the precipitation this evening and will likely make a couple more in the next couple of hours. Main change was to boost PoPs rather substantially tonight based on NAM Nest and HRRR continuing to indicate showers developing and moving through much of eastern PA and northern/central NJ. This is already bearing out to some degree, as showers continue to develop in Berks/Chester Counties southward into northern/northeast MD and westward into south-central PA. Hourly temperatures will be rather chaotic this evening as rain-cooled air will generate rapid changes to temperatures. The overall trend during the night is a little warmer/moister, so raised hourly temps/dews a couple degrees beyond 10 pm. Previous discussion... Elongated area of low pressure currently situated along a cold front over central PA extending north into upstate NY with a line of showers along this front moving east. Meanwhile, across the forecast area, we are in the warm sector with a southerly flow allowing temps to get well into the 60s with even some 70+ degree readings. As we go through the latter part of afternoon, the aformentioned cold front and line of showers will be moving east and should enter our western counties beginning by around 21z. Instability will be increasing as this occurs with high res models suggesting a few hundred J/kg of ML CAPE by the time the line moves in. Low level lapse rates will also be fairly steep with a fairly strong flow through the boundary layer and deep layer shear near 50 knots. For this reason, expect line to intensify with isolated thunder still possible. Also, showers and any storms could produce gusty winds and it`s worth noting that the Storm Prediction Center has placed most of eastern PA into NW NJ into a marginal risk for severe storms. This means a few locally severe storms could occur though we are not expecting this to be a significant widespread severe weather event. Damaging winds are the biggest threat. By around 8 pm this evening, showers should be reaching the I-95 corridor but instability will be decreasing by this time with any risk of thunder and severe weather quickly diminishing. Beyond this time, showers will continue pushing east through NJ as the front moves east with some indications some additional showers could re- develop just behind the front back toward the I-95 corridor by the later evening so we keep at least chance POPs in the forecast through this period. Precip should finally move out overnight as the front pushes off the coast and low pressure re-organizes over New England. Brisk NW winds will also be setting up by this time due to the strengthening pressure gradient between this low and high pressure over the midwest. Lows by morning will generally be in the upper 30s to mid 40s except mid 30s over the southern Poconos. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... For Sunday, upper level trough supporting the surface low described above will be closing off into a closed upper low over the northeast. This combined with the continuing brisk NW winds will result in a much cooler day with considerable cloud cover, especially north. Also, some scattered to isolated showers will be possible across the far north through the southern Poconos and it`s possible these could even be mixed with a little snow as highs here will only be in the low to mid 40s. Elsewhere, expect highs generally in the 50s. However NW winds 10-20 mph will make it feel cooler. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... The mid level pattern on Sunday night will feature troughs over the northeastern and northwestern states with a ridge up the middle of the country. The trough over the northwest is forecast to deepen as the ridge and the northeastern trough progress to the east. The axis of the ridge is expected to pass over our region on Tuesday night. Temperatures will start the work week below normal. However, the pattern change will result in well above normal temperatures late in the week. Surface low pressure will continue to lose its influence over our weather gradually during the period from Sunday night through Monday night. We are anticipating a good deal of cloud cover on Sunday night and Monday from the Poconos and the Lehigh Valley into northern and central New Jersey. We have included the mention of a low or slight chance of rain showers in those areas. Actually, we may end up seeing a fair amount of virga on Monday afternoon up there as the lower levels continue to dry. A partly cloudy sky is anticipated for northeastern Maryland, Delaware and southern New Jersey. The sky is forecast to become mostly clear for Monday night and Tuesday and temperatures should begin their rise to above normal levels. Surface high pressure is expected to become established over the western North Atlantic resulting in a south to southwest surface flow in our region from Tuesday into Friday. Warm and mostly rain- free weather is anticipated. Weak disturbances traveling over the ridge in the mid level flow may bring some showers and thunderstorms to areas to our northwest and north from late Wednesday into early Friday. The potential for any precipitation making its way into our northwestern counties appears slim but we have included the mention of a slight chance of precipitation there. Our best chance for showers and thunderstorms in the long-term period of the forecast is from Friday afternoon into Friday evening, ahead of a cold front approaching from the northwest. It appears as though the front will pass through our region on Friday night, with clearing anticipated for Saturday. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Tonight...Generally VFR with CIGs 4000-7000 feet, though brief MVFR CIGs/VSBYs may occur with showers. Showers may continue at most TAF sites off and on through the early morning hours, but should be done by sunrise (with possibly some scattering of the CIGs by this point). Winds becoming west-northwest 10 to 20 kts, potentially with gusts near any showers. Moderate confidence. Sunday...VFR with SCT-BKN CIGs near 5000 feet, especially during the late morning and afternoon. West-northwest winds 10 to 20 kts with gusts to 30 kts. Moderate confidence. Outlook... Sunday night through Thursday...Mainly VFR. && .MARINE... Made a lot of changes to the forecast and the current small craft advisory. With conditions nearing criteria already on Delaware Bay, bumped up the start time to 1 am for the bay and adjacent Atlantic waters. Meanwhile, delayed start time of the northern/central New Jersey coastal waters until tomorrow evening, when lapse rates may prove more favorable for mixing down the stronger west/northwest winds. Finally, extended the advisory for all locations through Sunday night based on the latest forecast guidance. Isolated showers/storms may occur tonight on the waters, with gusty/erratic winds and locally higher waves where these showers occur. The threat should diminish by Sunday morning. Outlook... Monday through Thursday...No marine headlines are anticipated. && .FIRE WEATHER... A northwest wind of 15 to 20 mph with gusts around 25 mph is anticipated for Monday afternoon. Relative humidity values are expected to drop into the 20s in much of southeastern Pennsylvania, southern New Jersey, Delaware and northeastern Maryland. If the forecast does not change, we will coordinate with our fire weather partners on Sunday to see if any special fire weather products should be issued for Monday. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory from 6 PM Sunday to 6 AM EDT Monday for ANZ450>452. Small Craft Advisory from 8 AM Sunday to 6 AM EDT Monday for ANZ453. Small Craft Advisory from 1 AM Sunday to 6 AM EDT Monday for ANZ430-431-454-455. && $$ Synopsis...Iovino Near Term...CMS/Fitzsimmons Short Term...Fitzsimmons Long Term...Iovino Aviation...CMS/Iovino Marine...CMS/Iovino Fire Weather...Iovino