Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/12/18


Area Forecast Discussion
National Weather Service Bismarck ND
959 PM CDT Fri May 11 2018 .UPDATE... Issued at 955 PM CDT Fri May 11 2018 Forecast looks to be generally on track. Updated the precipitation chances through the overnight using a blend of the latest iteration of a time lagged RAP and the previous forecast. Also blended the latest observations with the forecast and updated the overnight lows tonight and highs Saturday afternoon using the latest National Model Blend guidance. UPDATE Issued at 651 PM CDT Fri May 11 2018 No major changes are needed for this update. Expect a few isolated light showers to continue across the south for the next few hours. Blended the latest observations to the going forecast. && .SHORT TERM...(This evening through Saturday) Issued at 211 PM CDT Fri May 11 2018 Rain shower potential southwest and south central this evening and tonight highlights the short term forecast. Dry east-southeast surface flow with dewpoints in the teens and 20s F will limit rainfall potential generally north of a line from La Moure, to Garrison, and Watford city. The greatest rainfall will continue to be focused southwest where greater moisture resides coupled with upslope surface flow. The CAMs through the 18 UTC HRRR are generally in line with this thinking, however, did disregard their depicted precipitation across the north central this afternoon given the dry air in place. For Saturday, scattered rain showers may continue across the southwest and extreme south central with mid level diffluence and a few weak impulses ahead of the upper low across the Rockies. .LONG TERM...(Saturday night through Friday) Issued at 211 PM CDT Fri May 11 2018 A warming trend into early next week highlights the extended forecast. The 12 UTC global suite favors split upper level flow across the Northern Plains Sunday potentially transitioning to mean ridging by mid next week. This favors a warm up to potentially above normal values in the 70s and lower 80s by Monday and Tuesday, and potentially into Wednesday. The overall pattern favors sparse precipitation chances at best until late next week when the weak upper level ridge may break down. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 651 PM CDT Fri May 11 2018 Patchy light rain showers are scattered across the southern third of North Dakota and will continue on and off through much of the period. KDIK has been seeing some lower MVFR ceilings and that is expected to continue of the new several hours. KISN may come close to dipping into MVFR ceilings during the first part of the period, but most guidance has them holding on to VFR conditions. At all other sites, VFR conditions are expected through the period. Winds will generally be light and variable. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...ZH SHORT TERM...PA LONG TERM...PA AVIATION...ZH
Area Forecast Discussion
National Weather Service Boston/Norton MA
1004 PM EDT Fri May 11 2018 .SYNOPSIS... A warm front will stall near southern New England Saturday, bringing a rainy and cool day to the region. The stalled front will push south of the region Sunday, although a few showers may linger near the South Coast. Mainly dry weather follows early next week along with moderating temperatures. However, showers may return during the middle and later parts of the week as a cold front approaches. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 10PM Update... Low level clouds are currently over western New York and are expected to move into the region just after midnight. Given how much dry air is currently in the lower levels, rain showers may not be as heavy or as widespread as originally expected. The main swath of precip continues to trend slower, with the HRRR suggesting rain not entering the region until 12Z. The 00Z sounding out of Chatham, MA shows an inversion just above the surface, which if remains in place through tomorrow morning, fog could be possible across the region given the light winds and saturated low levels. No significant changes to the previous forecast. PREVIOUS DISCUSSION... Skies were clear except for a few clouds near Cape Cod Canal where there is some low level convergence present, which can be seen in surface wind fields. Still looks like sea breezes will try to form later this afternoon as pressure gradient weakens and winds aloft diminish. That looks to happen between 4 and 6 PM, so there may be some late day cooling along coast. After a clear start to the night, clouds presently over Great Lakes will arrive later tonight on as mid and high level moisture increases well ahead of warm front. There should be a quick drop in temperatures this evening across interior as winds become light, so some upper 30s are certainly possible with 40s elsewhere. Keeping forecast dry for tonight as it will take time for lower levels to saturate. Nothing more than 30-50 percent PoPs in CT and western MA toward sunrise, which is in line with HREF and other high-res guidance. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Wet and cool day on tap Saturday as warm front settles near South Coast. Models show decent moisture convergence below 850 mb coupled with PWATs near 1.5 inches and decent large scale lift as seen in Q-vector fields, so widespread rainfall of 0.25 to 0.50 inches seems reasonable. Upper flow is fairly progressive so our thinking is most of rain will end later Saturday afternoon, especially with weak short wave pushing offshore. E/SE flow will keep temperatures on the cool side, only in upper 40s to lower 50s. Front should push south of New England Saturday night behind departing short wave and weak surface low. Drying will be slow to follow given weak wind field, so expect clouds and patchy fog to linger. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Big Picture... High pressure sits over the West Atlantic as well as the Southeast USA. Closed low north of Hudsons Bay maintains broad shallow cyclonic flow, almost zonal, over the Northeast and Great Lakes through most of next week. Closed upper low over the Great Basin and upper high over the Pacific Northwest establish a temporary block early week, which gives way to another closed low that pushes in off the Pacific. A couple of shortwaves move through the almost zonal flow next week, one around Wednesday and a second around Friday. Given how late this is in the forecast period, some timing changes in these shortwaves should be expected. Model mass fields are similar through Wednesday, then show divergences in Western Canada that migrate through the flow to New England. Concerns... Cold front stalls south of New England, and with the near-zonal flow aloft there should be little to move the front off that position. The front retreats south Sunday, so dry weather is expected but with a cool east flow. The dry weather remains in place Monday and Tuesday with winds turning from the southwest. Mixing reaches 850- 900 mb each day, with temps at the top of those layers supporting sfc max temps 60s Sunday, 70-75F Monday, and 80-85 Tuesday. Wednesday through Friday look unsettled as at least one and possibly two shortwaves move through. These may generate a wave along the stalled front, drawing the rain shield north over some or all of our area. We also note a cold front moving south through Canada at this time. The shortwave may, with the right timing, pull this cold front south through New England. All of this is late in the forecast period, so the details such as rain-vs-showers are still subject to change. But it does look like an unsettled period. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Saturday Night/... 00z Update... Light winds continue across the region, with seabreezes possible along the coast between 00z and 2z this evening. KBOS Terminal...High confidence in TAF. BOS remains on the boundary of the seabreeze with NW winds, but with the trend to prevailing N winds early tonight, impact should be minimal on operations. Ceilings are expected to start lowering around 8Z, then lowering to 2000 feet around 16Z. KBDL Terminal...High confidence in TAF. Ceilings will lower around 6Z, becoming less than 2000 feet by 14Z. Outlook /Sunday through Wednesday/...Moderate confidence. Sunday: VFR. Breezy. Sunday Night: Mainly VFR, with local IFR possible in patchy BR. Monday through Tuesday: VFR. Tuesday Night: Mainly VFR, with local IFR possible overnight. Chance SHRA, slight chance TSRA. Wednesday: Mainly VFR, with local IFR possible. Breezy. Chance SHRA, slight chance TSRA. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Saturday Night/...High confidence. E/SE winds under 20 kt and calm seas (less than 4 ft) tonight and Saturday as front stalls near South Coast. Rain arrives Saturday morning and continues through early evening with 1-3 NM visibilities along with areas of fog. Winds back to N/NE Saturday night and remain under 25 kt but seas on outer waters south and east of Nantucket may build to 4 or 5 ft due to leftover swell. Outlook /Sunday through Wednesday/...Moderate confidence. Sunday: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers. Sunday Night: Winds less than 25 kt. Patchy fog. Areas of visibility 1 to 3 nm. Monday: Winds less than 25 kt. Local visibility 1 to 3 nm in morning fog. Monday Night through Tuesday: Winds less than 25 kt. Tuesday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers, slight chance of thunderstorms. Wednesday: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers, slight chance of thunderstorms. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && $$ SYNOPSIS...WTB/JWD NEAR TERM...Correia/JWD SHORT TERM...JWD LONG TERM...WTB AVIATION...WTB/Correia/JWD MARINE...WTB/JWD
Area Forecast Discussion
National Weather Service Cleveland OH
928 PM EDT Fri May 11 2018 .SYNOPSIS... Warm front over southern Ohio will move northward through Saturday afternoon. This front will stall south of Lake Erie as low pressure tracks eastward along it. The front should sag to southern Ohio on Sunday and remain there into next week. && .NEAR TERM /THROUGH SATURDAY NIGHT/... Update...Believe that the stationary/warm front to our south remains south of the area through most of the night based on HRRR forecast temps and winds. In keeping with that have held a cloud deck across the area throughout the night given the continued overrunning of the boundary. This represents an increase in clouds south vs the original forecast at least in the graphics. Also adjusted pops up across much of the area early overnight. Original...Active weather pattern with a frontal boundary wobbling across the region through Saturday night. Warm front will lift northward through the night reaching northern Ohio late Saturday morning. There will be showers and thunderstorms near and north of the boundary overnight. A stronger piece of jet energy will move across the area late tonight with lift being enhanced near it. This should allow for an increase in the strength of the thunderstorms as they track across Lake Erie. Locally heavy rainfall will need to be monitored with some training of showers/thunderstorms overnight. Especially across NE OH into NW PA. The morning round of showers/thunderstorms will have an impact on the location of the frontal boundary. Current thinking is that the front will be nudged southward. However that will leave the southern CWA in the warm sector with the heating likely boosting the strength of the convection. SPC currently has the southeastern portion of the area in an enhanced risk of severe thunderstorms. There will be more low level moisture to work with by Saturday afternoon so there will be a threat of heavy rainfall. A short fused flood watch may be needed. Cloud cover and showers have kept much of the area in the 50s today. The exception is across central Ohio where lower 70s are occurring. This warmer air will attempt to move northward on Saturday. Expect a large temperature swing from north to south. Highs in the 50s near the lake and near 80 across the extreme south. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... The area will remain primarily on the northern periphery of the quasi-stationary front on Sunday. The overrunning of warmer/more moist air will drive the baroclinic zone further north, with dew points climbing into the 60s over southernmost counties. The rain chances will remain over the southern-most areas and with no discernible shortwaves expected could see a break in the rain for northern lakeshore counties in the afternoon. No such luck in regards to clouds, with overrunning would anticipate mostly cloudy conditions in most areas. By Monday there appears to be a higher chance for some showers as another low trains eastward over the same meandering boundary. The airmass will gradually become more moist in the mid-levels, and low level dew points will be in the 60s for Monday with the potential for higher rainfall rates. The threat for flooding will increase as areas become worked over and saturated from on/off showers with storms likely to regenerate and train eastward over the same areas. The storms on Saturday will produce the saturated ground conditions that could set the stage for flooding later in the forecast, though too much uncertainty exists to pin point any particularly vulnerable location. It will not be raining constantly, however the large scale zonal flow continues to steer shortwave features into the upper Ohio Valley. && .LONG TERM /TUESDAY THROUGH FRIDAY/... The threat of rain continues into the long term forecast. Models trend toward next wave to move through on Wednesday. Models push the boundary south of the forecast area Wednesday night. Still some doubt as to how far south the boundary will go. ECMWF has next wave move across central and southern Ohio while the GFS has it south of the Ohio river. Will go likely pops for Wednesday then just keep chance pops going Wednesday night through Thursday. GFS has boundary waving north with low pressure tracking across Northern Ohio on Friday while the ECMWF is further south. For now will just keep chance pops going. && .AVIATION /00Z Saturday THROUGH Wednesday/... Warm front across central Ohio with overrunning rain from WI across mi, over Lake Erie and about to move into nwrn PA. Am expecting this area of precip to continue ese across nwrn PA through the evening hours with conditions dropping to MVFR at KERI by 03z. Guidance has more showers and thunderstorms developing to our west and tracking in across northwest OH/Lake Erie overnight so will need to monitor for potential development. Expecting the front to remain in central OH overnight before quickly lifting north Saturday morning to near a MNN-YNG line before stalling. Will keep most areas VFR through the overnight and then transition to MVFR/IFR Saturday after 10-12Z as front moves into the area and then drops south again bringing showers and a few thunderstorms to the area along with MVFR/IFR CIGS down from the north. OUTLOOK...Non-VFR in showers/thunderstorms Saturday night through Tuesday. && .MARINE... Northeast winds will strengthen tonight as a wave of low pressure moves east from Indiana along a quasi-stationary front just south of the lake. Winds will be 20 knots gusting to 25 knots mainly over the western basin. The low will move into PA early Saturday and the pressure gradient will relax. Waves will build to 4 to 6 feet in persistent fetch, but come down in the morning. The frontal boundary will sink further south on Saturday allowing high pressure over the upper lakes to move into the area. Weak shortwaves are expected to ride along this stationary front over the next several days. For the most part winds will be out of the north with the boundary south of the lake. The low pressure systems could strengthen winds but not looking at small craft through the forecast after tonight. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...Small Craft Advisory until 9 AM EDT Saturday for LEZ142>149. && $$ SYNOPSIS...Mullen NEAR TERM...TK/Mullen SHORT TERM...Jamison LONG TERM...DJB AVIATION...TK MARINE...Jamison
Area Forecast Discussion
National Weather Service State College PA
1031 PM EDT Fri May 11 2018 .SYNOPSIS... A nearly stationary front will remain over or near the forecast area through Sunday. The front will keep the pattern unsettled into next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... The region is north of the warm front that extends from southern OH eastward through central WV/VA. To the north weak waves aloft are bringing a chilly rain to northern PA and southern NY. This will continue overnight as strong warm advection on the nose of a 30-40 kt SW LLJ surges out of the OH valley into the local area. Have a mention of a small chance of thunder as some elevated instability is indicated by the near term models, but no severe is anticipated. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... High Res CAMs form a surface low over the OH/PA border north of PIT later tonight and early Sat morning. This is made to drag the warm north into central PA. Mainly cloudy and showery conditions will be in place along and just north of the warm front over my NRN zones, but in the warm sector breaks in the clouds should help developing the instability. The RAP forecasts a rapid destabilization over about the southern 1/2 - 2/3 of the forecast area as the low tracks through the state, with CAPEs in excess of 1500J/kg by early to mid afternoon. Shear will be impressive as a 50-70kt mid level westerly jet punches into the region. SPC has elevated the severe risk to ENHANCED and this looks reasonable given the expected thermodynamic setup. With the warm front in the vicinity, will have to remain aware of the threat for supercells and isolated tornadoes. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... Following what is shaping up to be an active afternoon and evening of severe weather across south-central PA on Saturday, T-storms should weaken but showers will continue into Saturday night across south-central PA. A quasi-stationary frontal zone dropping slowly south will remain the focus for periods of rain into Mother`s Day. It appears stability will increase over much of central PA on Sunday with plenty of clouds/moisture and east/southeast flow promoting much cooler temperatures vs. Saturday across the southern 1/2 of the area. Some locations over the interior north-central ridge and valley region may even struggle to get above 60F. Kept the highest precip probs over the southern 1/2 to 1/3 of the area along with maximum QPF, which seemed to better fit the frontal position and model blends. Some locally heavy downpours will remain possible on Sunday, but the overall risk for T-storms/localized flooding should be trending lower/further to the southwest closer to the expected instability placement. The pattern remains quite unsettled through next week as the frontal zone meanders over the Mid Atlantic region. Increasing moisture/dewpoints and above average PW all suggest a daily risk for showers and thunderstorms. Areas of locally heavy rainfall are possible, with the potential for multiple rounds of convection. The specific areas most likely to receive heavy rains will likely be somewhat difficult to pin down until the short term when models begin to resolve mesoscale/convective processes. An upper low developing across the northeastern Gulf of Mexico will supply additional moisture which is projected to advect northward toward the Mid Atlantic by Wednesday. This may set up a potentially more organized moderate to heavy rainfall scenario later next week as the deep moisture plume interacts with the nearly stationary west-east frontal zone. After a cool day on Sunday (Mother`s Day), expect temperatures to be above seasonal climate averages next week with a muggy summertime/humid feel given dewpoints in the 60s. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... A few showers and isolated thunderstorms have got going in the warm advection, southeast of the main area of showers to the northwest. Adjusted the late evening TAFS some, mainly using VCSH in some groups earlier. Earlier discussion below. Most of the showers gone now across the far north. Much of the overnight will be just mid lvl clds and VFR conditions. Expect the edge of the next cluster of showers across the central Great Lakes early this evening to drop southeast later tonight, which will bring conditions down to MVFR and IFR late tonight into Saturday. Left thunderstorms out for now, could see a few storms near the MD border from late morning into the mid afternoon hours, but less likely just to the north. While winds may shift to the southeast later, a lot of cool, dry air in place to work out of the area for storms. Outlook... Sun...Rain/low cigs possible. Mon...AM rain/low cigs possible. Tue and Wed...Scattered PM thunderstorm impacts possible. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte/Gartner NEAR TERM...La Corte/Gartner SHORT TERM...Dangelo/Gartner LONG TERM...Steinbugl AVIATION...Martin
Area Forecast Discussion
National Weather Service Wichita KS
643 PM CDT Fri May 11 2018 .SYNOPSIS... Issued at 325 PM CDT Fri May 11 2018 The forecast over the next several days will be dictated by a frontal boundary that is currently stalled nearly all the way across the middle of the CONUS extending eastward from an upper trough over the Central Great Basin. It is expected to remain in place through at least the beginning of next week. South of the frontal boundary, an influx of moisture from the Gulf of Mexico will continue to be transported into the region in association with a strong southerly flow regime that is expected to persist throughout the short term. Though mostly capped, this could bring several chances for showers or thunderstorms into the forecast area throughout the next several days. && .UPDATE... Issued at 636 PM CDT Fri May 11 2018 Plan to let wind advisory expire on schedule. Current thinking is any chance for storms will likely be closer to 0300 UTC or later and probably either in extreme northwest sections of forecast area or a bit further northwest, where 850MB convergence is better. -Howerton .AVIATION... && .SHORT TERM...(This evening through Sunday night) Issued at 325 PM CDT Fri May 11 2018 For this afternoon and evening, a couple of models (such as earlier HRRR runs and latest NAM) showed an area of convergence in southwest Kansas near the near the Oklahoma border sometime after 00z. It is possible that convergence along, near, or just south of the intersection of the front and dry-line could initiate a few isolated storms just to the west of the forecast area, which have the potential to make their way northeastward into the CWA in south central/central KS. Confidence in this remains fairly low, however, and potential looks to be a little lower than previously thought. If development should occur in the CWA, storm activity would be very isolated in nature, so have downgraded wording from slight chance to isolated for this evening and tonight. On Saturday, things look to stay mostly dry across the forecast area. Though atmospheric instability will be present in sufficient amounts during the afternoon and early evening, a strong cap should keep convective initiation at bay for the most part. Models are hinting that there could be a small window of cap breakage in south central Kansas where a storm or two could pop up, but not looking at anything widespread and the chance will be slim. Chances for thunderstorms start to become meaningful across the area by Sunday evening, when an eroded cap should allow some showers and storms to develop. At this point, shear looks to be relatively weak shear and lapse rates only modest, so am continuing with the notion that widespread severe weather is unlikely. However, a few strong or severe storms will be possible given CAPE near 2000J/kg in conjunction with the weakened cap. The latest convective outlook from the Storm Prediction Center agrees with this thinking placing central and south central KS in a marginal risk for severe thunderstorms, with hail and damaging winds as the main threats. .LONG TERM...(Monday through Friday) Issued at 325 PM CDT Fri May 11 2018 More chances for showers and thunderstorms will be possible to start the work week as the pattern becomes more active. The aforementioned surface front and an associated upper trough draped across the Central Plains and the middle Mississippi Valley will stall through at least Wednesday, bringing chances of showers and thunderstorms Monday evening and lingering again Tuesday through late Thursday. As of now, it looks like by the end of next week shower and storm potential will be confined to southeast Kansas before finally pushing off to the east. Temperatures are forecast to remain warm ahead of the stalled front for most of the area throughout the period. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 636 PM CDT Fri May 11 2018 Main forecast issue is location of front which has went through KRSL but not KSLN or KGBD. This this front will likely meander across central KS throughout the forecast period, so wind direction at KGBD is especially problematic. Models have not shown much consistency/skill so far with boundary placement and not optimistic with current runs either. Does appear to be some consensus for a bit of a south push tomorrow. MVFR ceilings possible in wake of front, but limited that to KRSL for now. -Howerton && .CLIMATE... Issued at 325 PM CDT Fri May 11 2018 Despite an April that averaged slightly cooler than normal for the area, May has been off to a very warm start. Due to recent well above normal temperatures experienced across central, south central, and southeast Kansas, decided to give a quick climate update. All climate sites (Chanute, Salina, and Wichita) have experienced well above normal afternoon high temperatures every day of the month so far. In fact, average highs for Wichita during the first 10 days of May ran a little over 10 degrees above average. Though no high temperature records have been broken so far this month, it is not out of the question in the coming days, and there have been multiple days that been quite close. Looking ahead in the long term, the Climate Prediction Center is currently forecasting for the warm trend to continue into the foreseeable future. In fact, CPC outlooks have the entire state of Kansas as warmer than average in every time period that it produces an outlook for (next 6-10 days, 8-14 days, 3-4 weeks, one month, and even three months). The current local forecast over the next week certainly supports this trend. The bottom line is that if the CPC outlooks verify we could be in for quite a warm summer. On the drought front, despite recent rainfall, the new US Drought Monitor still suggests that we are experiencing severe and extreme drought conditions across much of the area. The good news is that the forecast calls for multiple chances of rain throughout the next few days, and CPC indicates that above normal rainfall is expected over the next couple of weeks. The drought is currently forecast to remain in place, but is expected to improve a little over the coming weeks. && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 69 92 69 92 / 10 0 10 20 Hutchinson 67 90 64 87 / 10 0 10 20 Newton 69 90 66 90 / 10 0 10 20 ElDorado 69 89 68 91 / 10 0 10 20 Winfield-KWLD 70 91 69 93 / 10 0 0 10 Russell 59 78 55 81 / 10 10 10 20 Great Bend 62 81 58 84 / 10 0 10 20 Salina 65 87 60 86 / 10 10 10 20 McPherson 66 88 62 86 / 10 10 10 20 Coffeyville 71 89 68 92 / 10 10 0 0 Chanute 70 89 68 91 / 10 10 0 10 Iola 69 88 68 91 / 10 10 0 10 Parsons-KPPF 70 88 69 92 / 10 10 0 10 && .ICT WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 7 PM CDT this evening for KSZ052-053-069>072- 093>096-098>100. && $$ UPDATE...PJH SYNOPSIS...TAV SHORT TERM...TAV LONG TERM...TAV AVIATION...PJH CLIMATE...TAV
Area Forecast Discussion
National Weather Service Marquette MI
738 PM EDT Fri May 11 2018 .SHORT TERM...(This evening through Saturday) Issued at 436 PM EDT FRI MAY 11 2018 WV imagery and RAP analysis indicated confluent mid/upper level flow through the nrn Great Lakes between a ridge through the nrn plains and a trough over ne Canada. At the surface, high pressure from nrn Lake Superior to lake Huron was bringing light ne to e winds into Upper Michigan along with plenty of dry air. light rain supported by a weak shortwave trough and isentropic lift north of a warm front through nrn Missouri into cntrl IL. Mainly just high clouds prevailed over Upper Michigan. Tonight, given the very dry low level air over the region, expect the rain will remain south of Upper Michigan. Otherwise, mainly clear skies with favorable radiational cooling conditions will favor seasonably cold conditions with min readings from the mid to upper 20s inland and lower 30s along the Great Lakes. Saturday, mostly sunny skies with mixing through 850 mb temps around 6C will push inland max readings into the mid to upper 60s. This will also drop Min RH values into the 15-25 percent range resulting in increasing fire weather concerns. Fortunately, winds are expected to remain below 10 mph. .LONG TERM...(Saturday night through Friday) Issued at 436 PM EDT FRI MAY 11 2018 Models suggest that a split flow pattern will prevail into next week with the northern Great lakes dominated by confluent mid/upper level flow and sfc high pressure keeping the area dry. expect warming early next week and then more significant cooling after Wed as a weak nrn stream shortwave and cold front moves through. Sunday into Monday, WAA and 850 mb temps to around 11C Sunday will climb to near 14C by Monday supporting inland readings into the mid 70s Sun and to the lower 80s Monday. Light winds will favor prominent lake breezes and much cooler conditions along the Great Lakes. The lighter winds will also help keep fire wx concerns in check despite min RH values into the 20-25 percent range inland. Tuesday-Friday, expect a shortwave moving through nrn Ontario to drag a weak cold front through Upper Michigan. Since little moisture will be available and the stronger 700-300mb qvector conv with this features will remain well to the north, no significant pcpn is expected. However, max temps should drop back into the 50s and 60s with min readings in the 30s. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 737 PM EDT FRI MAY 11 2018 With high pres and a very dry air mass dominating, VFR conditions and light winds will continue thru this fcst period at KIWD/KCMX/KSAW. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 436 PM EDT FRI MAY 11 2018 Could see SE winds gusting to around 20kts Sun into Sun night, but otherwise expect relatively light winds. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...JLB AVIATION...Rolfson MARINE...JLB
Area Forecast Discussion
National Weather Service New York NY
1054 PM EDT Fri May 11 2018 .SYNOPSIS... High pressure moves east of the area tonight, followed by a warm front that will stall just south of the area Saturday. Weak waves of low pressure will then move along the stationary front through Sunday. Weak high pressure will build into the region briefly on Monday with a frontal boundary residing just south of the region through much of next week. A cold front will push through the region late Tuesday night and into Wednesday and stall just south of the region for the remainder of the week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Zonal Mid-Upper level flow will become increasingly active overnight into Saturday, with several perturbations moving through the flow. High pressure slides east overnight, while a warm front across the Ohio Valley and Mid Atlantic will lift towards the region overnight. This front will likely stall well to the south Saturday morning, but it will have surface flow shifting to a maritime east-northeasterly component t the north of it. Meanwhile deep SW/W flow aloft will advect a warm and moist airmass over the region, with a rapidly increasing likelihood of rain west to east across the region overnight. Radar trends, in addition to latest HRRR and NAM, are indicating that rain will move in much quicker, with shower activity quickly overspreading the region from west to east after midnight through the overnight. Elevated instability will also present a chance of embedded thunderstorms and locally heavy rain across at least western portions of the CWA late tonight into Saturday morning. Temps are expected to run near to slightly above seasonable with increasing cloud cover. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Rapid warm/moist advection will continue into Saturday morning above about 925 mb as an upper trough rotates towards New England and a series of short waves advect east- southeastward in strong west- northwest flow. PWATs will quickly increase to around the 90th percentile for this time of year. Elevated instability should be sufficient enough for at least isolated convection. Given the west-east oriented frontal boundary and flow largely parallel to it, there is potential for training cells, with multiple rounds of convection leading to the possibility of rainfall amounts higher than forecast. WPC has placed northern NJ in a marginal risk for excessive rain, and it`s certainly not out of the question that this risk could extend eastward into Long Island. Northwest flow is a notoriously difficult flow pattern to forecast with precision, so any subtle shift in the warm frontal boundary could lead to significant differences in the forecast tomorrow. As of now, the warm sector is forecast to remain south, where a threat of severe weather will be possible tomorrow and temperatures will be much higher than to the north of the boundary. Should the front set up farther north, a risk of wind and perhaps even an isolated tornado will be possible. The forecast will need to be monitored closely. Instability appears to wane after around 06Z Sunday, though the threat of rainfall will continue as the pattern remains unsettled. High temperatures will be around 10 degrees below climatological normals, though there remains uncertainty depending on the exact location of the warm front. Lows overnight Saturday will be closer to normal. && .LONG TERM /SUNDAY THROUGH FRIDAY/... A split flow regime is indicated by the global model guidance over the CONUS through the period, with a somewhat zonal and progressive flow to start for our region. The true northern branch of the jet stream will remain north of the region with the southern branch and a cut off low over the deep south. Over time the southern branch is expected to undergo some amplification with most model guidance hinting at increasing chances of unsettled weather late next week and into the following weekend. As far as some details, a difficult forecast to say the least for Sunday with last night`s NAM hinting as some suppression with a shortwave and indicating dry weather, at least for northern parts of the CWA. However the 12z NAM was further north with forcing and precip and would not be surprised to see model oscillation for another run or so as far as Sunday and into Monday morning. For now most of the guidance has Monday being a mainly dry day, but clouds may linger with the location of the frontal boundary that will be plaguing us in doubt. Clouds further south and thinning of clouds further north looks to be the consensus for Monday, with a better chance at some sun further north and later in the day. Tuesday at this point looks to be mainly dry, before the aforementioned amplification of the southern branch attempts to get underway and lower latitude moisture begins to stream further north by Tuesday night and into Wednesday. The timing of this has differed with some of the global models so not the highest confidence forecast for the mid to late week. Current thinking is the chances for periods of unsettled and wet weather will increase, if not by Tuesday night, then by Wednesday. A cold front will slide down from the north and northwest approaching for late Tuesday night into Wednesday , then stalling for the second half of the week with the chance for periods of unsettled weather continuing. The most difficult question to answer is whether or not Canadian high pressure to our north will attempt to build in for Thursday into Friday as hinted at by some of the 12z global guidance (GFS and GEM). A blend of the global model guidance is preferred at this time. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... High pressure moves off the New England coast through the overnight with a wave of low pressure approaching along with a warm front. This front will become stationary Saturday, and set up in the vicinity of the terminals, across southern Pennsylvania to south of Long Island. There is some uncertainty as to where the front will be Saturday. VFR through the overnight with a chance of showers developing by 05Z west, and around 08Z east. Showers become more widespread by 07z and MVFR conditions may develop before sunrise. Conditions are expected to quickly lower to MVFR, with areas of IFR as showers become widespread early Saturday morning. There will be a chance of isolated thunderstorms, mainly during the afternoon. Winds will be northerly, then NE overnight, generally less than 10 KT. Saturday winds will be NE to E through the day, generally 10 KT or less. Wind directions are uncertain, and there is low confidence in the wind forecast, which will be highly dependent on the placement of the stationary front. .OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY... .Saturday night...MVFR to IFR in -SHRA, isolated TSTM, and fog. .Sunday...Chance of -SHRA with MVFR conditions. Conditions may improve to VFR in the afternoon. .Monday...Chance of showers early in the morning. MVFR becoming VFR. .Tuesday...VFR. .Wednesday...MVFR possible with -SHRA, isolated TSTM in afternoon. && .MARINE... Brief high pressure moves east of the area overnight before a warm front stalls over or just south of the ocean waters tomorrow, then shifts southward overnight Saturday as a surface high passes to the north. Winds and seas will remain relatively tranquil through this time period, though there will be a chance of thunderstorms over the water on Saturday. Winds and waves should remain below SCA criteria through Tuesday. Seas do start to approach SCA levels out on the ocean waters by Wednesday when a southerly swell starts to dominate. && .HYDROLOGY... 3/4 to 1 1/4 inches of rain is likely Saturday into Sunday, with locally higher amounts possible. There is potential for training thunderstorms producing localized heavy rainfall. At this point the more likely threat would be minor urban and poor drainage flooding, but there is a low threat for localized flash flooding. Periods of unsettled weather are expected for the middle and latter half of next week. There is the possibility of intervals of embedded moderate to heavy rainfall, however predictability of timing and location of any impacts is low. && .EQUIPMENT... NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) remains off the air. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...MD/JE NEAR TERM...MD/NV SHORT TERM...MD LONG TERM...JE AVIATION...19 MARINE...MD/JE/NV FIRE WEATHER... HYDROLOGY...MD/NV/JE EQUIPMENT...