Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/10/19

National Weather Service Albany NY
939 PM EST Sat Mar 9 2019 .SYNOPSIS... A low pressure system approaching from the south and west will bring widespread precipitation to the area late tonight into Sunday. Initially snow is expected, then will quickly transition to a wintry mix Sunday morning, and then rain by Sunday afternoon for most of the area. Blustery conditions with some snow and rain showers will occur Sunday night into Monday in the wake of the storm system. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... Winter Weather Advisory now in effect for all areas for late tonight through Sunday afternoon... Wind Advisory for the southern Green Mountains, southwest Adirondacks, central/northern Taconics and Berkshires for Sunday... As of 930 PM EST, high clouds are steadily increasing across the region. Temps have dropped off in some northern and eastern sheltered areas into the lower/mid 20s, while remaining generally in the mid 20s to lower 30s elsewhere. Wind has persisted in many areas before the high clouds arrived, preventing temps from falling as much as previously forecast. Where clouds remain somewhat thin, temps could still drop to around 20 across portions of the southern Adirondacks and Glens Falls area, southern VT and the Berkshires over the next couple of hours, while only dropping to 25-30 elsewhere. The clouds should thicken toward and especially after midnight, tempering any falling temps, and in fact, as winds become east/southeast, temps should start rising in some areas. Models, most notably near-term models such as the RAP13, HRRR and also HREFs continue suggest a slower onset of precipitation, as the departing ridge axis sharpens in response to strengthening pressure/height falls to our west. However, as the leading edge of a potent low/mid level jet approaches, expect precipitation to quickly overspread the region between roughly 4 and 6 AM EDT from west to east. Thermal profiles suggest mainly snow to start, although as a mid level warm nose quickly advances northeast, some sleet could mix in as soon as after an hour or two of snow from the Capital Region area of NY and points south and west. Snowfall rates could be between one half inch and one inch per hour while all snow occurs, so a quick inch of snow is possible before the changeover to sleet in these areas. Farther north and east, the snow will just be starting, so accumulations through 6 AM EDT should remain under an inch, although snow may be falling moderate to heavy at times shortly after commencing. East to southeast winds will increase across higher terrain areas of the SW Adirondacks and eastern Catskills, with some gusts of 30-40 mph possible toward 6 AM Sunday, with stronger gusts possible shortly thereafter across the SW Adirondacks. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/... Sunday, a band (fitting the "laterally translating" paradigm per CSTAR research) of moderate to locally heavy precipitation should continue advancing quickly east/northeast between 6 and 8 AM EDT. Mainly snow is expected for the Mohawk Valley, southern Adirondacks, and southern VT as this initially moves through, with snowfall rates possibly as high as 1-1.5 inch/hour. However, sleet should mix in after 1-2 hours of snow. Thus, a quick 1-3 inches of snowfall is expected between roughly 6 and 8 AM EDT in these areas, with perhaps another 1-2 inches in portions of the SE Adirondacks and higher elevations of southern VT of snow/sleet after 8 AM EST. Elsewhere, mainly sleet and freezing rain is expected through mid morning Sunday before changing to plain rain from south to north. Ice accretion should range from a trace, to up to one tenth of an inch, with greatest amounts across higher terrain areas of the eastern Catskills, Helderbergs, and Litchfield Hills. As a strong low level jet segment translates across the region, strong wind gusts of 40-50 mph will be possible across higher terrain areas of the southern Greens, northern/central Taconics, Berkshires, and SW Adirondacks (mainly extreme northern Herkimer and Hamilton Counties) where a Wind Advisory is in effect from 6 AM EDT Sunday until 4 PM EDT. There is a possibility that the advisory may need to be expanded slightly southward in time into the southern Taconics and Litchfield Hills, and trends in upstream observational data will need to be watched. Despite the strong low level jet passing overhead, strong wet bulbing of the initially dry and chilly air mass may create quite a shallow low level cold pool that may be very difficult to dislodge Sunday, particularly across northern areas such as the southern Adirondacks, eastern/central Mohawk Valley, the Lake George/Saratoga region and portions of southern Vermont (especially higher terrain areas of eastern Bennington County) east to the CT River Valley in SE VT, as well as across northeast Berkshire County. In these areas, spotty light freezing rain/freezing drizzle may persist into at least the early to mid afternoon hours Sunday. Elsewhere, after the initial burst of snow/sleet and some freezing rain, expect only spotty light rain/drizzle and some areas of fog for the afternoon hours. Late afternoon high temps should range from the mid 30s portions of the southern Adirondacks, eastern Mohawk Valley and Lake George/Saratoga region into portions of southern VT and northeast Berkshire County MA, to the upper 30s to lower 40s elsewhere. Sunday night-Monday, an occluded front should move across the region Sunday evening with some rain showers in valley areas, and snow showers across higher terrain areas. Some minor accumulations of 1-2 inches could occur in northern Herkimer County. Otherwise, expect a brief period of clearing for areas south and east of I-90/I-88 Sunday night, with clouds and lingering snow showers/flurries to the north and west. Clouds should expand south and east during Monday, with persistent snow showers across the SW Adirondacks, and isolated to scattered snow/rain showers farther south and east into the Mohawk Valley and southern VT. West to northwest winds will increase during this period, with gusts of 25-35 mph developing later Sunday night, and 35-45 mph Monday. Will have to watch for any deeper mixing potential for Monday afternoon, as this would increase the possibility for gusts to reach up to 50 mph, especially within the Mohawk Valley/Capital Region and Berkshires. If this potential increases, then a Wind Advisory would be issued for these areas. Lows Sunday night mainly in the 30s for lower elevations, and upper 20s across higher terrain. Highs Monday reaching 40-45 in most valley areas, with 30s across higher elevations, where temps may fall during the afternoon. Monday night-Tuesday, as the upper level trough passes through Monday night, snow showers may increase in areal coverage before diminishing later at night into Tuesday, and contracting to areas closer central NYS with a veering low level wind flow. Expect increasing sunshine for Tuesday after some morning flurries/snow showers across western areas. It will be breezy, but not quite as windy as Monday, with highs reaching the mid 30s to near 40 in valley areas, and 25-30 across most higher elevations. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... The period starts out Tuesday night with a ridge of high pressure both at the surface and aloft building eastward across the region. With light winds and clear skies this will result in a cold night. After a cool start to the day Wednesday, temperatures will moderate to near normal levels during the afternoon as the surface anticyclone shifts eastward off the coast and a return southerly flow develops. The upper level ridge will remain in place though, so dry conditions will persist with minimal cloud cover. The upper ridge axis will then move over the region Wednesday night, and shift east of our area on Thursday. This is when temperatures are expected to warm to above normal levels, due to strengthening low level southwest flow. Model guidance (especially the 12Z ECMWF) has backed off on any precip through at least the first half of Thursday, so will mention dry conditions through early afternoon then introduce a chance of showers late in the day as a frontal boundary approaches. Will trend forecast towards slower ECMWF for Thursday night into Friday, with mainly chance pops for rain showers, as a weak boundary meanders across the region. Ahead of this boundary, temperatures could soar well into the 50s across much of the area and could reach 60s in some parts of the Hudson Valley. A deep snow pack will limit significant warming in higher terrain areas though. QPF looks too high from the GFS at this time, with only weak forcing present. The first in a series of cold fronts will push through Friday night, with some tempered cooling behind this boundary and some light showers. Additional showers will be possible on Saturday associated with another cold front. Temperatures expected to cool closer to normal on Saturday. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... High pressure will remain in control through this evening and into the overnight hours. A low pressure system will then track into the Great Lakes region, with a warm front approaching from the south and west during Sunday. Clear to partly cloudy skies are expected through about 08Z/Sun with VFR conditions. Clouds will quickly thicken thereafter, with precipitation quickly developing between 10Z-12Z/Sun from southwest to northeast. Vsbys should quickly drop to IFR as precipitation begins (mainly as snow and/or sleet), with MVFR Vsbys. Initially, the precipitation should start as a snow/sleet mix at KALB, KPSF and KPOU, before changing to mainly sleet, then freezing rain and sleet between roughly 12Z- 14Z/Sun. Snow/sleet accumulations of around an inch, and a light glaze is expected at KALB and KPOU before precipitation changes to plain rain by 15Z/Sun. At KPSF, freezing rain may linger until 18Z/Sun before changing to light rain or drizzle. At KGFL, where cold air will be a bit more pronounced, precipitation should start as snow, and could be briefly moderate to heavy, before mixing with and/or changing to sleet between 14Z-16Z/Sun, then freezing rain and sleet between 16Z- 19Z/Sun. After 19Z/Sun, mainly light rain or drizzle is expected. Snow/sleet accumulations of 1-3 inches are possible at KGFL, along with ice accumulations of up to one tenth of an inch. For Sunday afternoon, steady precipitation should taper off to patchy drizzle or rain showers. However, MVFR Cigs will persist, with VFR to MVFR Vsbys. Winds will be variable around 5 kt or less, becoming east- southeast around 8-12 kt by early Sunday morning. A southeasterly low-level jet is expected to move over the region Sunday morning, which will allow for low level wind shear to develop, especially at KPOU/KPSF where wind speeds aloft should be strongest. Winds may become more northerly at KGFL during the morning and into the afternoon due to localized terrain effects. Outlook... Sunday Night: Moderate Operational Impact. Chance of SHRA. Monday: Moderate Operational Impact. Windy With Gusts To 35.0 Slight Chance of SHRA...SHSN. Monday Night: Moderate Operational Impact. Breezy Chance of SHSN. Tuesday: Low Operational Impact. Breezy NO SIG WX. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: No Operational Impact. NO SIG WX. Wednesday Night: No Operational Impact. NO SIG WX. Thursday: Moderate Operational Impact. Chance of SHRA. .HYDROLOGY... No hydrologic issues are anticipated through the middle of next week. A moderating trend is expected over the weekend into next week to near seasonable levels. However, snowmelt is expected to remain negligible, especially across higher terrain areas the seasonable temperatures will only act to slightly ripen the existing snowpack. A low pressure system will bring widespread precipitation to the area late tonight into Sunday. Current forecast is for around a half inch across most of the area, to about two-thirds of an inch across far southern portions of the area. At least half of that amount is expected to fall as snow/sleet. Other than some lake effect snow in some areas on Monday, dry conditions are expected until late next week. There are some signs for above normal temperatures later next week, which could result in more significant snowmelt and river rises/ice movement, depending on the magnitude of the warm air and how long it will last. 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...Winter Weather Advisory from 4 AM to 1 PM EDT Sunday for CTZ001-013. NY...Winter Weather Advisory from 4 AM to 1 PM EDT Sunday for NYZ047>054-058>061-063>066. Wind Advisory from 6 AM to 4 PM EDT Sunday for NYZ032-033-054- 061. Winter Weather Advisory from 4 AM to 5 PM EDT Sunday for NYZ032-033-038>043-082>084. MA...Winter Weather Advisory from 4 AM to 1 PM EDT Sunday for MAZ025. Wind Advisory from 6 AM to 4 PM EDT Sunday for MAZ001-025. Winter Weather Advisory from 4 AM to 5 PM EDT Sunday for MAZ001. VT...Wind Advisory from 6 AM to 4 PM EDT Sunday for VTZ013-014. Winter Weather Advisory from 4 AM to 5 PM EDT Sunday for VTZ013>015. && $$ SYNOPSIS...KL/NAS NEAR TERM...KL SHORT TERM...KL/DBT LONG TERM...JPV AVIATION...KL/JPV HYDROLOGY...KL/NAS
Area Forecast Discussion...CORRECTED
National Weather Service Gaylord MI
942 PM EST Sat Mar 9 2019 .UPDATE... Issued at 942 PM EST Sat Mar 9 2019 There are many, many ways in which this forecast could go awry. Right out of the gate, the only county without an advisory (Manistee) is seeing advisory-level wind gusts (49 mph peak gust at MBL) as precip (liquid, at least at MBL) starts to move in. There are some power outages in that area. That`s small potatoes compared to the briefly (very) heavy wintry mix lifting into the area. Highest QPF during the night remains in the sw half of the forecast area, and in particular Gladwin/HTL/W Branch - the newest RAP dumps almost exactly an inch of liquid precip on top of HTL tonight (though the HRRR is far less wet). That high- end QPF forecast looks far, far too wet. Various model soundings in this area are riding the ragged edge of snow vs sleet vs freezing rain, though with the latter two being favored. Not sure the se zones (HTL-W Branch) see a quick burst of all snow at the beginning, and will back off a bit on snow there to add more sleet and even a touch of ice. However, there are no locales that reach 0.25" of ice accum. Will add Manistee Co to the advisory for a few hours (added to the group that expires at 1 am EST). Updated advisory will also play up the easterly winds tonight a bit more. Otherwise, changes to this point are minor. && .NEAR TERM...(Through Tonight) Issued at 347 PM EST Sat Mar 9 2019 ...Another unfavorable storm track for easy precipitation type forecasting tonight... High Impact Weather Potential: Another precipitation type nightmare...with a lot of possibilities. Pattern Synopsis/Forecast: Early afternoon surface analysis shows 991mb low near Kansas City...with 7-8mb/3h pressure falls over northeast Missouri/northwest Illinois (barograph is stair- stepping downward rather sharply this afternoon). This low is expected to make more of a northeast turn this evening toward southern Lake Michigan...eventually winding up in the vicinity of Grand Traverse Bay by Sunday morning. Expansive band of precipitation continues to push northeast out of the Mississippi Valley and toward the upper Great Lakes...with rain spreading across Indiana/northern Illinois. Meanwhile a rather pleasant afternoon across northern Michigan with a thickening blanket of high clouds and some gusty east- southeast winds...but temperatures have warmed nicely with a few spots (TVC/ACB) having touched 40. But dew points are down in the single digits and teens...these 20-30 degree dew point depressions will prove problematic for tonight`s precip type forecast. Primary Forecast Concerns: Approaching system from the southwest will be pushing precipitation and warmer air north tonight...the combination of a developing elevated warm nose and much uncertainty regarding how low wet-bulbing temperatures will go make the precip- type forecast a bit tricky. Eastern Upper...Expect areas above the bridge to remain dry through early evening before precipitation advances in from the southwest during the mid-late evening hours. Precipitation should be widespread into the early morning hours before some semblance of dry slotting may turn things more freezing drizzly or showery for a time. Precipitation type in general should be mostly snow though warm nose may sneak into far eastern Upper late tonight. Gusty easterly winds will create some issues with blowing/drifting snow as well...though overall snowfall should be on the wetter/more dense side given nearly 400mb deep layer of temperatures above -10c (more accretion/aggregation/riming cutting down on snow-liquid ratios). Think a solid 2-4 inches is a decent range for snow totals tonight. Northern Lower...Precipitation type much more problematic here given initial dry low levels as mentioned an initial warm layer aloft may erode quickly once precipitation starts especially across interior northern Lower. There could be a decent burst of snow at the onset of the precipitation from the M-55 north to the M-32 corridor and east of M-37 where a quick 3-4 inch burst of snow not out of the realm of possibility. West of M-37 precipitation precipitation could start as snow/sleet before changing to rain/ freezing rain. Again how far surface temperatures drop is an unknown given large temperature/dew point spreads...but it seems reasonable that temperatures may hang around or a bit below freezing for a good part of the night in the hills of Grand Traverse/Wexford Counties. So eventually some ice accumulation may be problematic... but a lot of uncertainty here. Heading north of M-72 expect precipitation to spread in as the evening progresses...likely to fall as mostly snow (some sleet at the onset with evaporative cooling)...eventually transitioning to more liquid precipitation during the pre-dawn hours. eastern Upper some mid level drying will complicate precipitation types with some periods of freezing drizzle overnight. As temperatures warm aloft higher terrain areas across interior northern Lower may hang around freezing for a longer period of time. Also with gusty winds some blowing snow issues probable. Headlines...Will re-jigger the headlines around spatially and temporally (reason number 400 why I`m not a fan of second period advisories). Will push the start time of the eastern Upper advisory into late evening...end time of Sunday afternoon will remain the same. Not comfortable ending much of the northern Lower advisory this evening...especially if surface temperatures are slow to recover (e.g., higher terrain) and there ends up being a longer potential window for freezing rain/icing. The exception will be Gladwin/Arenac counties which will be added to the advisory (matches DTX) but just through 05z. Otherwise it`s easier to cancel early if conditions improve rather than trying to decide whether to extend a headline farther out in time. Nor am I comfortable leaving Grand Traverse and Leelanau counties out of the advisory...the latter in particular since they may see more frozen/freezing precip types much of the night and Sunday morning (they will be chunked in with the far northwest Lower advisory that runs through Sunday). Grand Traverse and Benzie will be added through 05z and then the headline can be re-evaluated (especially with respect to interior Grand Traverse County). Will leave Manistee county alone for now. && .SHORT TERM...(Sunday through Tuesday) Issued at 347 PM EST Sat Mar 9 2019 High Impact Weather Potential....Mainly moderate snow in E Upper as the freezing rain departs by the early morning. Pattern Synopsis/Forecast...The models came in colder today, too as the track shifted a little more south than yesterday at this time. By 12z/Sun the sfc low is somewhere between the Bridge and KPZQ as depicted by the GFS and ECMWF (or KCVX if you throw in the 12z NAM or near Atlanta on the 18z NAM), so some where north of M-32. This pushes the 850 mb cold air off the Lake Huron shoreline and with the moisture in the 850-700 and 700-500 layers > above 85% will figure that the chance for freezing precipitation will be done, and snow or a rain/snow mix will be the case. The 850 mb temperatures are around -8c and the water either frozen or around +2c where the water is open. Think that lake enhancement low as the instability will be 10C or less to start, but pick up as the temperatures drop overnight to around -11c by 12z/Mon. Monday, the 850 mb temperatures are dropping to around -13c, with moisture in the 850-700 mb layer around 55%. So there will be some LES as the system continues to move NE out of the Great Lakes. The RH in the layer will continue to dry out through the day, so will expect that the LES will diminish. Monday night, the 850 mb temperatures warm to -5c by 12z/Tue and the rh in the layer drops to < 20% so will expect that all the snow will stop sometime in the evening or overnight. Primary Forecast Concerns...Snow amounts look to be light to moderate as the rain/snow mix changes to the snow in E Upper and N lower. The amounts in N lower will be light as it will take a little longer to transition to all snow. The wind gusts continue to not show much over 40 mph as the models are showing 30-35 knots at 950 mb and 925mb Sunday evening. This makes the the winds getting to 15 to 25 mph with gusts to 35-40 mph, so that the areas of blowing and drifting are expected. If there is a trouble spot, it could be around KCVX as the winds over the ice/snow blow onshore and cause issues wind gusts could be 40-45 mph from around Grand Traverse light to near Bay Harbor if the HiResW models are right. .LONG TERM...(Tuesday night through Saturday) Issued at 347 PM EST Sat Mar 9 2019 High Impact Weather Potential...A storm on Wednesday/Thursday could bring a mix of rain and snow. Extended (Tuesday through Saturday)...Tuesday will be a quiet day as the high pressure from Monday moves through the Upper Great Lakes. Tuesday night, the next system begins to moves into the region, and spreads snow during the evening and overnight. Wednesday, the system moves into the C Plains, and continues to spread the precipitation around the Upper Great Lakes. This one looks like it is mostly rain, with the threat of a mix as we head into Thursday and Thursday evening. The 500 mb low doesn`t move into the Upper Great Lakes until Friday, which is more likely for the mix. Friday night, the mix will turn to snow, and the snow will continue into Saturday as a 500 mb low drops into the Upper Great Lakes and brings another chilly shot of cold air. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 626 PM EST Sat Mar 9 2019 Deteriorating conditions from south to north tonight. Low pressure will move ne from the mid-MS Valley, and will be near TVC at 12Z. Mixed precip will advance northward into the region, falling initially as mostly snow, then mixing with sleet, freezing rain, and just rain. Places further south (MBL) will see more in the liquid precip, while further north (PLN) will see more in the way of snow. IFR conditions will eventually develop, and LIFR is at least briefly possible. Mix snow and rain will linger for much of Sunday. Gusty e/ese winds will diminish somewhat late tonight as the low approaches. Gusty west winds return behind the low on Sunday. LLWS tonight. && .APX WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY until 6 AM EDT Sunday for MIZ017-018-023- 024-027>030-032>036. WINTER WEATHER ADVISORY until 6 PM EDT Sunday for MIZ016-019>022. WINTER WEATHER ADVISORY until 1 AM EST Sunday for MIZ025-026-041- 042. WINTER WEATHER ADVISORY until 6 PM EDT Sunday for MIZ008-015. && $$ UPDATE...JZ NEAR TERM...JPB SHORT TERM...JL LONG TERM...JL AVIATION...JZ
Area Forecast Discussion
National Weather Service Boston/Norton MA
946 PM EST Sat Mar 9 2019 .SYNOPSIS... High pressure exiting E overnight as clouds spread across the region. A wintry mix for Sunday morning changing over to rain as late as Sunday afternoon out ahead of a storm sweeping across the Great Lakes. High pressure slowly builds over the region, cresting on Wednesday and moving off to the east Thursday. This will mean dry weather and seasonable temperatures through most of the workweek. A storm ejecting from south of California will move through the Great Lakes Friday, spreading rain over Southern New England with lingering showers Saturday. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... 945 pm update... Previous forecast is on track. An abundance of mid level cloudiness will be overspreading the region from the west over the next few hours. This should keep temperatures mainly steady in the middle 20s to the lower 30s overnight. Dry weather should prevail overnight through about 5 am, before a burst of snow/sleet overspreads the region through mid morning Sunday. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... */ Highlights ... - Wintry mix onset Sunday morning, eroding N with warmer air - WINTER WEATHER ADVISORIES for N CT, NW RI, Central and W MA - Blustery SE winds with gusts to 40 mph across coastal MA and RI - Possible roadway water ponding SE MA / RI per snow-clogged drains */ Overview ... Warm-frontal upslope / over-running event associated with an inside- runner Great Lakes storm. Preceding cold air damming and N drainage winds especially for the CT / Pioneer River Valleys, forecasting an onset snow early Sunday morning transitioning to sleet / freezing rain then to plain rain over the interior, while transitioning to sleet then to rain across the coast / coastal plains throughout the morning hours into afternoon, concluding towards evening. Generally speaking, a coating to around 3 inches of snow / sleet for most of S New England. A trace and not going above a tenth of an inch of ice accretion for NW RI, N CT, W and Central MA where a WINTER WEATHER ADVISORY remains posted. GALE WARNINGS expanded over the S waters. */ Details (associated with 12z guidance) ... Thermal fields ... SE Canada situated high pressure with interior low pressure over the Great Lakes, shallow cold air drainage with H97-95 ageostrophic / isallobaric flow especially over CT / Pioneer Valley. More of an E onshore component over S/E New England. Meanwhile over- running warm nose around H8, subtle nuances / model differences, how- ever leading into the event, global model H85-7 thicknesses colder than high-res guidance. Same can be said with the maximum wet-bulb temperature within the H9-5 layer. Prior forecaster made mention as to the NAM tending to do well with mid-level warm noses, however the forecast may be complicated by forcing / dynamic cooling that delays onset of warmer air yielding more snow or sleet, plus aforementioned cold air drainage aiding with colder low-levels and subsequent re- freezing towards sleet. Perhaps precip-transition delays also by signaled surface - H85 pressure falls sweeping over SE New England Sunday afternoon that could hold longer / tuck colder air over CT / Pioneer River Valleys. Preference to colder 1000-850 mb thicknesses while warmer 850-700 mb thicknesses suggested by high-res guidance. Forcing ... Speaking of, model consensus warm-frontal over-running ascent and convergent mid-level SW winds yielding NW-SE H5-7 fronto- genesis extending through the snow growth region with 15-25 microbar per second omega early Sunday morning. SREF suggesting a brief burst of snow / sleet with low probabilites of 1" per hour snowfall rates over N/W MA and N/W CT. Both less than the prior event last weekend. Frontogenesis transitioning to H925-85 coincident with surface - H85 1 to 2 mb per hour pressure falls sweeping across SE New England by Sunday afternoon, subsequently aided by H925-85 low-level convergent wind enhancement. Considering this along with forecast precipitable waters around 0.75 inches, running +1-2 standard deviations above average for early March, there`s a question as to how much liquid equivalent will result. Precipitation ... So compared to the last weekend`s event, forcing not as robust however a more moist environment. Model consensus has generally 0.40 to 0.80 storm-total liquid with highest amounts over S/SE-coastal New England. But looking at model soundings along with the latest HRRR / RAP model output, lot of dry air to overcome below H5 initially. Onset by a few hours later into Sunday morning mainly beginning after sunrise. A daytime event, lowered slightly snow totals but kept ice totals roughly the same. Slight uptick in liquid equivalent given +3-4 standard deviation above average H85 moisture flux. Winds ... Surface to H85 pressure falls over SE New England coupled with a localized enhancement in H925-85 low-level winds in proximity, while taking into account a stout inversion, still expect gradient- driven SE winds of 30 to 40 mph centered around midday Sunday over coastal MA and RI as well as adjacent waters. Roughly 20 to 30 mph over the coastal plains and high terrain. Closer to high-res and MOS guidance with respect to CT / Pioneer River Valley winds preferring a N-drainage flow. As pointed out by the prior forecaster, a +2-3 standard deviation above average of H925-85 winds. Hazards ... Given an average 1 to 2 inches of snow-water equivalent in the snowpack, especially over interior SE New England which saw around 8 to 14 inches last Monday, clogging drains as solid walls of ice along roadways, can`t rule out ponding of water along roadways in isolated spots. Snow ratios 8-12:1 and sleet ratios 2-3:1, a consensus blended with aforementioned storm-total liquid, yields a coating up to around 2 inches of snow / sleet, highest amounts up to 3 inches over the N Berkshires. High-res preference of thicknesses, layer maximum wet-bulb, and 2m temperatures, a trace up to a tenth of ice accretion over NW RI, N CT, W and Central MA. Opted not to expanded E as consensus has icing mostly W of the MA I-495 beltway. Yes, there`s icing in the forecast around I-495 but think the impact will be minimal during the daylight hours compared to the W where winter weather headlines exist. Expansion of GALE WARNINGS on the waters per wind discussion above. && .LONG TERM /MONDAY THROUGH SATURDAY/... Big Picture... Longwave scale shows trough west and ridge east at the start of the week, which then transitions to ridge west and trough east late week. A two-part shortwave trough lingers over the Northeast USA Monday-Tuesday before moving off in favor of a ridge that covers the Eastern USA. Closed low along the California coast sweeps south to Northern Mexico, then ejects northeast midweek and crosses the Great Lakes by Friday. Contour heights at 500 mb over New England are a little below normal Monday-Tuesday, then climb above normal Wednesday through Friday. Expect, after a cool start to the week, a warming trend through the rest of the week. Model mass fields are in good agreement through Thursday morning. Upper contour fields then diverge for the end of the week, while sea- level isobars remain similar in indicating a Great Lakes storm with New England in a mild airflow. Confidence in the forecast is high through Thursday and moderate Friday. Low confidence Saturday. Concerns... Monday through Thursday... One shortwave moves off to the east Monday. A second shortwave sweeps through New England Monday night-Tuesday. Cold advection Monday afternoon and night with coldest temps at 500 mb at -30C Monday night. Warming temps aloft Tuesday. Moisture cross sections show increasing moisture 925 mb to 700 mb Monday night which then dissipates on Tuesday. Expect a period of partly cloudy skies. Flurries possible especially in the hills. High pressure then builds over the region. Expect mostly clear skies and light wind from Tuesday night through Thursday morning. Cross sections show increasing moisture above 700 mb Thursday afternoon but lots of dry air below 700 mb. We will forecast dry weather through Thursday afternoon, then chance pops for showers Thursday night. Friday-Saturday... Low pressure ejects from Northern Mexico, crossing the Great Lakes Friday and sweeping a cold front across our area Friday night- Saturday. New England is in a southwest flow and the temperature column is above freezing from surface to well above 800 mb. High pressure is over the ocean, with no mechanism to hold in low-level cold air. Expect showers, possibly as early as Thursday night and more likely Friday-Saturday. Convective parameters show a weak theta- e ridge Friday and total-totals around 50, while LI values remain above 5. Will keep an eye on potential for thunder, but too early to forecast with confidence. Pacific atmospheric river feeds into the West Coast storm as it moves into Northern Mexico. Once the storm crosses into the Plains, it draws upon more moisture coming out of the Gulf of Mexico. Interesting to see GFS forecast of 2 inch precip water values over Western Louisiana Wednesday afternoon. Per sounding climatology, that is 2-3 std deviations above normal for them this time of year! Most of this moisture becomes trapped in convection over the Deep South. But values of 1 to 1.25 inches reach to Southern New England by Friday, which is 2-3 std deviations above normal for us as well. This suggest a potential for downpours with this front, and will also need to be monitored. Final shortwave moves through the Northeast USA Saturday, but each model shows a different location. For now we will show chance pops across the northern half of our area. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Sunday Night/...High confidence. Tonight ... Mostly clear skies to start, but clouds increase during the night. Bases are above 15K through midnight and then lower overnight. VSBYs lower towards morning in the west to MVFR with onset of a wintry mix (SN/PL/FZRA) towards 12z, coastal RA. Coastal E/SE winds increasing 10 to 15 kts with potential gusts up to 30 kts along S-coastal terminals. Lighter 5 to 10 kt interior N drainage flow, mainly within N/W MA and CT terminals. Sunday ... CIGs and VSBYs IFR-LIFR with wintry mix transitioning over to all RA northward morning into afternoon. E/SE winds 10 to 20 kts with gusts up to 35 kts morning into afternoon pushing further W into the interior with only the CT / Pioneer River Valley hold with lighter N winds, transitioning W/SW late and becoming light. LLWS threats developing late morning into afternoon with S winds 50-60 kts at 2 kft agl, especially over S/SE MA and all of RI terminals. Sunday night ... Winds shifting W as terminal conditions improve towards VFR. IFR- MVFR CIG and VSBY conditions lingering across E / SE coastal terminals as late as roughly 6z Monday. KBOS Terminal... SN/PL developing around 12z Sunday, mixing with RA closer to 15z, turning all RA by 18z. Potential LLWS threats briefly around 22z with 180/50kt 2 kft agl. Clearing out and threats diminishing by 0z Monday. KBDL Terminal... SN/PL developing around 11z Sunday, mixing with FZRA briefly towards 18z by which point all RA prevailing. N flow through Sunday afternoon, overall light around 5 to 10 kts. Will see an improving trend beginning 22-0z Sunday into Monday as winds shift W. Outlook /Monday through Thursday/... Monday through Monday Night: VFR. Windy with local gusts up to 30 kt. Tuesday: VFR. Windy with areas of gusts up to 30 kt. Tuesday Night: VFR. Breezy. Wednesday through Thursday: VFR. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Sunday Night/...High confidence. GALE WARNINGS expanded over the S waters. While the main storm center sweeps across the Great Lakes, a secondary low may take shape over SE New England. A local enhancement in the wind profile aloft in addition to pressure falls should increase the local gradient wind profile. SE winds gusting up to 40 kts pushing 8 to 12 feet, the height of both around Sunday afternoon into Sunday evening. Winds should begin to diminish as they shift out of the W Sunday night allowing seas to subside. Outlook /Monday through Thursday/... Monday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Monday Night: Moderate risk for Small Craft Advisory winds with local gusts up to 30 kt. Seas up to 5 ft. Tuesday: Moderate risk for Small Craft Advisory winds with local gusts up to 30 kt. Local rough seas. Tuesday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of seas approaching 5 ft. Wednesday through Thursday: Winds less than 25 kt. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...Winter Weather Advisory from 5 AM to 2 PM EDT Sunday for CTZ002>004. MA...Winter Weather Advisory from 5 AM to 2 PM EDT Sunday for MAZ002>004-008>012-026. RI...Winter Weather Advisory from 5 AM to 2 PM EDT Sunday for RIZ001. MARINE...Gale Warning from 1 PM to 8 PM EDT Sunday for ANZ231>234. Small Craft Advisory from 6 AM Sunday to 2 AM EDT Monday for ANZ230-236. Gale Warning from 10 AM to 6 PM EDT Sunday for ANZ235-237. Gale Warning from 10 AM to 10 PM EDT Sunday for ANZ250-254-255. Small Craft Advisory from 6 AM Sunday to 8 AM EDT Monday for ANZ251. Gale Warning from 7 AM to 6 PM EDT Sunday for ANZ256. && $$ SYNOPSIS...WTB/Sipprell NEAR TERM...Frank SHORT TERM...Sipprell LONG TERM...WTB AVIATION...WTB/Sipprell MARINE...WTB/Sipprell
Area Forecast Discussion
National Weather Service Billings MT
835 PM MST Sat Mar 9 2019 .UPDATE... Area of snow showers extending from the Beartooth/Absarokas to the Bighorns is dissipating, and skies are mostly clear across the remainder of the region. Have reduced pops based on latest radar trends. Livingston has already fallen to 5 degrees so have dropped their expected low a bit...but would anticipate temps bouncing around through the night. HRRR has backed off on fog development later tonight but not quite buying it as daytime snow melt added moisture to the boundary layer, and skies are generally clear. Will sustain patchy fog in the forecast from 06-15z, mainly in river valleys. JKL && .SHORT TERM...valid for Sun and Mon... Skies have cleared across a good portion of our forecast area this afternoon as the shortwave responsible for last night`s snow has moved east. An elongated upper low exists to our west, extending from Oregon to western Montana. Lapse rates are fairly steep underneath this low, and latest satellite imagery shows convective snow showers developing over central Idaho and western Montana. BLX radar shows snow showers over the Beartooth Absarokas with a band extending to near Columbus. Scattered snow showers and flurries will continue across our western and southern mountains and foothills from now through mid evening. Models do not paint QPF as far off the foothills as Billings, but quick look at a HRRR forecast sounding shows steep lapse rates moistening thru the dendritic layer, so feel we could see some late afternoon and evening flurries here locally. Any lower elevation accumulation should stay less than an inch, but mountains could see a fast inch or two in heavier snow showers. Eastern areas will be dry this evening, and all lower elevations will be dry overnight. The combination of recent precipitation and daytime snow melt will bring the potential for fog tonight. HRRR shows splotchy fog in our east only, but feel the boundary layer is moist enough that western valleys could radiate cold enough for some fog as well. Upper low to our west will settle over the southwest CONUS and the resulting split flow will bring us dry and warmer conditions Sunday and Monday. Highs in the 30s tomorrow should warm to the upper 30s and 40s for a good portion of our forecast area by the beginning of the work week. Of course, the abundant snow cover will make forecasting temperatures difficult, but as 850mb temps rise to a few degrees above zero would be surprised if the foothills don`t see 50 degrees on Monday. Winds will also be on the increase in our west and that will help with the warming, as well as the snow melt, and will need to keep an eye on water runoff and/or ice jam issues over the next few days. JKL .LONG TERM...valid for Tue...Wed...Thu...Fri...Sat... A split flow aloft along with weak ridging on Tuesday will give way to a southwest flow aloft as an upper low and trough move onto the Pacific Northwest coast into the Great Basin area. Dry conditions and mild temperatures will continue on Tuesday with temperatures looking to be the warmest day in the extended with 30s to lower 40s common. Models organize this trough and upper low over the four corners region and southern plains on Wednesday then shift it northeast across the central plains and midwest during the day Thursday. This storm track is further east than what models were showing yesterday. As a result, the heaviest precipitation looks to remain east of Montana, although the southeast portions of the state will still need to keep an eye on this track. However, general troughiness will be over the northern rockies along with an upper low over Idaho during this time. This will result in temperatures cooling back into the 20s and 30s along with a chance for snow across our forecast area Wednesday and Thursday. Models then bring weak ridging, a dry northwest flow aloft, along with some moderating temperatures for Friday into next Saturday. Hooley && .AVIATION... Patchy fog and LIFR-IFR conditions are possible over southern MT and north central WY after 06z Sunday. This will be mainly in the river valleys. The best chance to impact a terminal will be around KMLS, but cannot rule it out around KBIL and KSHR. Otherwise, VFR will prevail at area terminals tonight. Ongoing snow over the mountains will taper to scattered snow showers later tonight...but mountains will remain obscured through the night. RMS/Reimer && .PRELIMINARY POINT TEMP/POPS... Sun Mon Tue Wed Thu Fri Sat ----------------------------------------------------------- BIL 013/034 018/042 022/042 020/037 022/034 015/035 017/037 00/U 00/U 00/U 13/O 41/E 10/B 10/B LVM 002/035 010/041 014/037 016/029 014/029 010/032 013/035 00/U 00/N 00/U 24/S 21/E 01/U 11/B HDN 005/033 006/039 013/041 015/036 019/034 010/034 012/035 00/U 00/U 00/U 14/S 52/S 10/B 00/B MLS 006/028 005/034 013/037 015/033 020/030 012/030 011/030 00/U 00/U 00/U 13/S 41/N 00/B 00/B 4BQ 005/032 006/039 015/041 014/034 019/031 012/032 012/033 00/U 00/U 00/U 03/S 52/S 00/B 00/B BHK 006/027 005/035 018/037 016/031 020/029 012/027 009/028 00/B 00/U 00/U 02/S 32/S 00/B 00/B SHR 009/034 009/043 018/044 018/034 019/031 012/034 014/036 10/U 00/U 00/U 03/S 53/S 10/B 00/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$
Area Forecast Discussion
National Weather Service Quad Cities IA IL
749 PM CST Sat Mar 9 2019 .UPDATE... Issued at 745 PM CST Sat Mar 9 2019 Have expanded the wind advisory to include counties along the Highway 20 corridor. Latest trends with the RAP, HRRR and NAM indicate periods where winds will increase into advisory criteria later tonight and Sunday morning. && .SYNOPSIS... Issued at 311 PM CST Sat Mar 9 2019 A strong, negatively tilted upper level shortwave was located over north central MO into south central IA at 3 pm. At the surface, the low was just north of Kansas City. An axis of strong 3 hour pressure falls of 9 mb/3 hours was centered near Peoria, with a tight pressure gradient around the entire system leading to strong gusty winds. Area radars showed the dry slot lifting the initial axis of warm advection rains north of I-80, while showers and thunderstorms, some with small hail, were advancing through northeast Missouri, southeast Iowa and west central Illinois, driven by steep mid level lapse rates and strong mid and upper level forcing ahead of the shortwave. As the low tracks east-northeast, the local area will have showers and thunderstorms, then possible dense fog, followed by strong winds in the cold air advection and pressure rises in its wake. && .SHORT TERM...(This Evening through Sunday) ISSUED AT 311 PM CST Sat Mar 9 2019 Bottom Line Up Front Will be hoisting a wind advisory for all but the Highway 20 corridor for tonight. The possibility does exist that the wind advisory may have to be extended into Sunday. Also, there has been some persistent dense fog to the north and northeast near the main surface low. There may or may not be a need for a headline regarding the fog this evening prior to the winds coming up. Tonight Assessment...medium confidence on precipitation timing. High confidence on the potential for high impact weather. Based on pressure falls, the main low looks to pass between Cedar Rapids and the Quad Cities. As the low moves up through the area, the risk for thunderstorms will dissipate during the evening. Also, there is a potential for dense fog to develop near the low as it moves through the area. Starting around mid-evening precipitation will end from south to north and winds will increase. Based on winds across Kansas wind gusts up to 45 mph are expected and a few gusts may reach 50 mph. Some snow is possible prior to the rain ending in the highway 20 corridor. Amounts would be a dusting at best. On Sunday, windy and dry conditions are expected as cold air moves into the area. I cannot completely rule out the possibility of some flurries occurring during the morning hours. .LONG TERM...(Sunday Night through Saturday) ISSUED AT 311 PM CST Sat Mar 9 2019 Sunday night through Monday night Assessment...high confidence Quiet and dry conditions will be seen as high pressure quickly moves through the Midwest. Temperatures will average below normal. Tuesday Assessment...low to medium confidence The first part of a more significant storm system will move through the area. There are differences between the models in regards to the timing of this system. The ECMWF and CMC global bring the first part in Tuesday afternoon while the GFS and FV3 bring the first part in Tuesday morning. As a result of these differences the model consensus has slight chance to chance pops all day Tuesday. If the first part of the storm system arrives Tuesday morning, precipitation will be in the form of snow that changes to rain. If the system arrives in the afternoon, precipitation will be in the form of all rain. Tuesday night on... Tuesday night through Thursday Assessment...high confidence on a storm occurring. Low confidence on the track and precipitation type. Another significant storm system will affect the Midwest Tuesday night through Wednesday night. All global models have the main surface low passing through the western half of Iowa and moving into Minnesota. Such a track would place the area in the warm sector with precipitation having a high probability of being all rain. Warm air being pulled north would also bring the risk of some thunderstorms as well as temperatures averaging above normal. However, there are some differences in timing with the storm system. Right now the model consensus has likely to categorical pops Tuesday night through Wednesday night. For Thursday the model consensus has slight chance to likely pops with the highest pops over the northwest third of the area. The bulk of the rainfall looks to be centered around late Tuesday night through Wednesday evening. Thursday night through Friday night Assessment...low confidence A fairly strong upper level disturbance will move through the Midwest. However, there are differences in the overall timing of the disturbance moving through the Midwest. Colder air aloft will create an unstable atmosphere and forcing acting upon the available moisture should be enough to generate light precipitation across the area. The model consensus has slight chance to chance pops Thursday night through Friday night for much of the area. Precipitation should be mainly rain during the daytime but may mix with or change to all snow at night. Saturday Assessment...medium confidence The model consensus has dry conditions for the area as the next high pressure starts moving through the Midwest. Temperatures will average below normal. && .AVIATION...(For the 00Z TAFS through 00Z Sunday Evening) ISSUED AT 529 PM CST Sat Mar 9 2019 Strong area of low pressure moving from northern Missouri to central Illinois will keep poor flying conditions in place for much of this TAF period. Area of rain and snow currently impacting KDBQ/KMLI/KBRL will move out of the area this evening, with dry conditions expected by 10/02z. As the low moves by, there will be the potential for some areas of fog as winds briefly diminish. Current KCID ob is showing misty conditions with MVFR visibility, so included a TEMPO group there through 10/02z. Any fog potential will be short lived as west winds quickly pick up after the low pressure passes, with gusts up to 30 kts at times. Conditions will slowly improve across the area Sunday, with several models hinting at VFR by 10/18z. && .HYDROLOGY... Issued at 1134 AM CST Sat Mar 9 2019 Forecasted rainfall still looks to average between 0.5 and 1.00 inch today into this evening. This rainfall falling over a saturated and frozen ground will runoff fairly quickly into area waterways. Additional runoff in the form of snow melt will also occur while temperatures are above freezing. Another storm system is forecast to affect the Midwest around the middle of next week. Rainfall and temperatures above freezing will result in another round of rises on area waterways that may push additional rivers into flood. Rock river: The forecast rainfall and expected snow melt will now push the Rock river into moderate flood. Additional rises are expected with the next round of rain late next week that is expected to push the river even higher. The situation with the ice jams between Lyndon and Prophetstown has not changed over the past 24 hours. Route 78 remains open but water is at the edges of the pavement. Rainfall and temperatures above freezing may cause water levels near the ice jams to fluctuate rapidly. Iowa river: New flood watches were issued for the Marengo and Lone Tree areas. The river will rise in response to the rain and snow melt that occurs today but will remain below flood stage. The next round of rain and snow melt next week will cause the river to rise again that may push it above flood stage. Pecatonica river: A flood watch was issued for the Pecatonica area. The river will rise in response to rain and snow melt today but is expected to remain below flood stage. The next round of rain and snow melt next week will cause the river to rise again that may push it into flood. Mississippi river: A flood watch was issued for the Gregory Landing area. Two rounds of rises will occur in response to rainfall and snow melt over the next 7 days that may push the river into flood. && .CLIMATE... ISSUED AT 311 PM CST Sat Mar 9 2019 Week 2...March 17-23 Odds favor below normal temperatures and below normal precipitation in this time frame. Below normal temps will help ensure the snowpack in Minnesota/Wisconsin does not melt too quickly. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...Wind Advisory until 7 AM CDT Sunday for Benton-Buchanan-Cedar- Clinton-Delaware-Dubuque-Jackson-Jones-Linn-Scott. Wind Advisory until 7 AM CDT Sunday for Des Moines-Henry IA- Jefferson-Lee-Van Buren. Wind Advisory until 7 AM CDT Sunday for Iowa-Johnson-Keokuk- Louisa-Muscatine-Washington. IL...Wind Advisory until 7 AM CDT Sunday for Bureau-Carroll-Henry IL- Jo Daviess-Putnam-Rock Island-Stephenson-Whiteside. Wind Advisory until 7 AM CDT Sunday for Hancock-Henderson- McDonough-Warren. Wind Advisory until 7 AM CDT Sunday for Mercer. MO...Wind Advisory until 7 AM CDT Sunday for Clark-Scotland. && $$ UPDATE...Speck SYNOPSIS...Sheets SHORT TERM...08 LONG TERM...08 AVIATION...Speck HYDROLOGY...08 CLIMATE...Wolf
Area Forecast Discussion
National Weather Service Grand Forks ND
941 PM CST Sat Mar 9 2019 .UPDATE... Issued at 938 PM CST Sat Mar 9 2019 Main 500 mb short wave is lifting into northern Wisconsin with snow ending from the south thru southern MN and snow ending slowly from the east thru the Red River valley. This trend to continue with the heavier snow shifting to our far eastern fcst area which hasnt had as much as farther west. At least that is the forecast and right now see no reason to alter the messaging of this. Though it would appear Bemidji/Park Rapids area will see the lower end of the 8-12 range vs the higher end of the range farther west. Winds are not playing a factor in NE ND and in the advsisory area where snow is now all moved out will drop advisory. Will leave warning as is, though likely a good portion can be expired early toward morning. Some wind gusts 35 mph or so southern RRV but even that isnt affecting vsby once snow ends as snow is quite wet and needs a lot more wind to blow it or drift it. && .SHORT TERM...(This evening through Sunday) Issued at 344 PM CST Sat Mar 9 2019 Negatively tilted mid/upper level trough axis just west of our CWA with small mid level circulation apparent near our southern CWA. RAP analysis showing axis of strong 700MB frontogensis orientated northeast to southwest across the Red River Valley along with axis of negative EPVg. This matches radar trends which show narrowing/intensifying snow band and we should see an uptick in snow rates. This also matches expected trend reflected in high res guidance, and while residence time of this band is more uncertain further north, we should still see potential for additional 3-7" or within the RRV (totals 6-10"). Further east stronger moisture advection in axis of WAA continues to rotate north and this will result in more accumulations there before this band moves eastward. This allows for possible 8-12" totals for parts of west central/northwest MN depending again on residence time of band. Model mixed layer winds still support potential gusts to 35 mph, though with wet snow there are still questions to how much impacts there will be if this period of wind occurs after snow ends. Before wind increases this evening, most significant vis restrictions will be due to heavy snow alone (some locations reported 1/4sm or less already). Still, blowing/drifting remain possible this evening/overnight before gusts start to decrease after midnight. Regarding headlines: no changes made as most intense period of this system for our CWA is getting underway. Any adjustments will be delayed until this evening when we see how this band evolves and begins to transition east of the RRV. Still expect our western CWA to see more improvement this evening and if blowing snow is less of an issue products could be ended this evening. .LONG TERM...(Sunday night through Saturday) Issued at 344 PM CST Sat Mar 9 2019 For Sunday night through Tuesday, a quiet period occurs as warmer, seasonal air builds into the Northern Plains as split flow aloft merges into upper level ridging over the central U.S. For Tuesday through early Wednesday, strong warm air advection over portions of the Northern and Central Plains coupled with a weak shortwave aloft will induce precipitation chances across portions of the area. Model forecast soundings suggest potential for freezing rain and/or drizzle as a strong low level warm nose develops Monday night into Tuesday morning. In this period, QPF is likely to be less than a tenth of an inch with the best chances for precipitation in northwest MN and possibly little to no precipitation west of the RRV. As surface temperatures increase through Tuesday, precipitation is expected to gradually transition to rain. Of greater concern is widespread precipitation chances building across the Northern and Central Plains Wednesday afternoon through Thursday as a strong Colorado low tracks from western Kansas to the Great Lakes region. This system looks to bring a wet period with around a half inch to inch of QPF across southeast ND and the northwest quarter of MN and a much greater uncertainty in amounts for areas further north and west. At this point, the most likely scenario is an initial predominant cold rain period as temperatures remain near or above the freezing mark and a transition to snow occurring Wednesday night or Thursday. A strong surface pressure gradient behind this system coupled with mixing an anomalously strong 850mb jet streak yields potential for blowing snow Thursday and perhaps Thursday night. However, with temperatures hovering around the freezing mark, there is low confidence in any details regarding precipitation type and amounts at any given location at this time. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 708 PM CST Sat Mar 9 2019 IFR conditions in vsby in snow for all but DVL basin this evening with improving conditions slowly into GFK by 06z and then rest of the area later tonight/Sunday AM. Once snow ends ceilings will rise and expect VFR balance of Sunday daytime. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...Winter Storm Warning until 1 PM CDT Sunday for NDZ027>030-038- 039-049-052-053. MN...Winter Storm Warning until 1 PM CDT Sunday for MNZ001>003-005- 006-008-009-013>017-022>024-027>032-040. && $$ UPDATE...Riddle SHORT TERM...DJR LONG TERM...BP AVIATION...Riddle
Area Forecast Discussion...UPDATED
National Weather Service Green Bay WI
820 PM CST Sat Mar 9 2019 New Information added to update section .UPDATE... Issued at 809 PM CST Sat Mar 9 2019 No headline changes planned this evening, though will be reshuffling the zone configuration a bit in the next WSW update. The primary band of precipitation with the cyclone tracking into the region continued to lift north across the forecast area. After an hour or so of mixed precipitation across the southern two tiers of counties in the area, the precipitation changed to snow due to evaporative cooling. Some very heavy snow has occurred, with a Co-op observer in Plover reporting nearly 2.5 inches of snow in an hour. The primary band will continue to shift north, and northern Wisconsin is cold enough for all snow with any precipitation of consequence. Strong forcing is still present in the wake of the primary band, so expect additional development to occur and feed into the southern portion of the band. But the new development is unlikely to reach the intensity of precipitation with the main band. Which is fortunate for the going forecast, because it would not take too long to sail right past forecast snow amounts if the high snowfall rates were to persist for too long. Satellite indicates some mid-level drying behind the primary band, so it is possible precip could change to FZDZ during lulls. Will refresh the hourly grids and forecast shortly, but the gist of the going forecast remains on track. UPDATE Issued at 542 PM CST Sat Mar 9 2019 The main surge of precipitation associated with a mature cyclone tracking northeast from the Central Plains has reached the area. The air at low levels was very dry, with surface dew point temperatures around 20F and the zero-degree (C) maximum wet-bulb temperature aloft isotherm completely south of the area on local meso plots. This indicates there will be significant evaporative cooling with the onset of precipitation, likely causing a transition to heavy snow across much of central and east-central Wisconsin within an hour or so after precipitation begins. There may be a tendency to flop back to more of a mix once the heaviest radar returns shift through. Have handled with with an SPS, and will re-evaluate snow totals for this area shortly. && .SHORT TERM...Tonight and Sunday Issued at 234 PM CST Sat Mar 9 2019 The latest RAP analysis and satellite/radar imagery show a potent area of low pressure centered over northeast Kansas early this afternoon, while high pressure prevails along the east coast of the conus. A wide arcing band of precipitation is lifting northeast across Minnesota through Illinois, and starting to work into southwest Wisconsin. Ample dry air emanating out of the departing high have slowed down the precip slightly, and the latest short range models show the precip starting to move into central WI and the southern Fox Valley in the 4-5 pm time frame. Precip continues to look like a mix at arrival time due to the below freezing surface wet bulb temps and warmer air pushing in aloft. As the low swings northeast tonight, forecast concerns revolve around potential snow and ice accumulations. Tonight...Low pressure remains on track to move northeast across northern Illinois and into northern Lower Michigan. The strongest forcing will push across the area during the evening, via a 50kt low level jet and associated moisture transport, mid-level fgen, and dpva ahead of the shortwave. As a result, should see most of the precip occur during the evening, though comma head precip should continue through the rest of the night. Models continue to indicate that the surge of warm air aloft only grazes east-central WI for a couple hours during the evening. Progged soundings also indicate that moisture above the -10C temp line will also be lost at times over parts of central and northeast WI this evening. The combo of warm air aloft and loss of ice crystals continue to suggest some ice/sleet accumulations roughly south of a line from Mosinee to the tip of the Door Peninsula, most likely highest over east-central WI. This will eat into the potential snow accumulations somewhat in this area. In general though, 3-6 inches of snow accumulations is a solid bet across most of the area, except for 1-3 inches over parts of east-central WI. Despite gusty east to north winds, the heavy/wet nature of the snow should limit blowing and drifting somewhat. No adjustments to the inherited advisory look necessary even with the slower timing, as start times line up with surrounding offices, and the potential ice accumulations continues to justify an advisory for east- central WI. Sunday...Low pressure will continue to lift away from the region into northeast Ontario. Light comma head snowfall will likely continue for most of the area early in the morning before ending from south to north through midday or early afternoon. Additional accumulations could reach up to an inch across far northern WI, but most likely will remain under an inch. Cloudy and windy conditions should then persist through the rest of the day. Gusts up to 35 mph will be possible, which could lead to some blowing and drifting of the lighter weight snowfall, especially over northern WI where the higher snow to liquid ratios will occur. Highs ranging from the low to mid 30s over most of the area. .LONG TERM...Sunday Night Through Saturday Issued at 234 PM CST Sat Mar 9 2019 The main concern in the extended portion of the forecast will be the potential rainfall/flooding potential for the middle of the workweek along with above normal temperatures. Sunday night through Tuesday: A surface ridge and increasing 500mb heights will be in place through this time period, bringing an extended break in the precipitation along with warmer temperatures. In fact many places will warm to near normal by Tuesday afternoon. Highs Monday will be around 30 while high temps warm to the mid and upper 30s for Tuesday. Overnight lows will be chilly with lows dropping down into the teens Sunday night and to the single digits above and below zero for Monday night. Leaned toward the colder guidance for Monday night with high pressure over the area, clear skies and PWAT values around 25 percent of normal. Wednesday through Thursday: The next southern stream piece of energy is expected to eject out of the Four Corners region into the central Plains Tuesday night into Wednesday morning. This would likely lead to rapid cyclogenesis across the Oklahoma and Texas Panhandles Wednesday morning. The low is then expected to lift northeastward, reaching western or central WI late in the day Thursday. This would keep most of the CWA in the warm sector, keeping the precipitation mainly in the form of rain. There could be a brief period of mixed precipitation early Tuesday evening, but this should quickly transition to all rain for the rest of this time period. Of greatest concern will be how much rain falls out of this system as it traverses the area. It looks like there will be plenty of moisture for the system to work with as the surface isobars remain wide open to Gulf moisture through much of this time period. PWAT values are progged to be around 1.0 to 1.5 inches for this time period, which is roughly 200 percent of normal for this time of year. A strong southerly LLJ is progged to develop ahead of this system, which will allow moisture to quickly advect northward into the CWA along with much warmer temperatures. Actually, most of the models are pushing 850mb temperatures up to around the +6 to +10C range Wednesday into Wednesday night. This would allow temperatures to warm well above freezing through this time period with most locations warming well into the 40s and possibly even pushing 50 in a few locations. The combination of increasing dewpoint temperatures (above freezing/mid to upper 30s) and warmer temperatures will start melting some of the snow across the area; however, this will take some time as the snowpack is fairly dense and will take time to ripen to the point where rapid melt would take place. The bigger concern will be largely focused on the potential for an inch or so of rain to fall (GEM/GFS) on frozen ground and across areas that may have poor drainage due to ice/snow clogging. The latest 12Z model run of the EC has less QPF, closer to a half inch or so. There will of course be some contribution from melting snow, but the bigger issue will likely be any significant amount of rain that falls, which may lead to at least localized flooding concerns. Rest of the extended: A cold front will then pass through the area ushering much colder air and a fairly deep upper-level trough for Friday. This will effectively put the brakes on any snow melt issues and help to lock in any water making its way through the snowpack. Otherwise, temperatures will fall back well below normal with highs only expected to reach into the upper 20s and low 30s for Friday into Saturday. && .AVIATION...for 00Z TAF Issuance Issued at 542 PM CST Sat Mar 9 2019 A band of heavy precipitation in the northern quadrant of a mature cyclone tracking northeast from the Central Plains will push across the area this evening, taking aviation conditions down to IFR/LIFR. LLWS is also likely this evening as winds aloft increase with the approach of the storm. && .GRB WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 10 AM CDT Sunday for WIZ022-031- 035>040-045-048>050-074. Winter Weather Advisory until 1 PM CDT Sunday for WIZ005-010>013- 018>021-030-073. && $$ UPDATE.........Skowronski SHORT TERM.....MPC LONG TERM......Cooley AVIATION.......Skowronski
Area Forecast Discussion
National Weather Service Grand Rapids MI
1037 PM EST Sat Mar 9 2019 LATEST UPDATE... Update .SYNOPSIS... Issued at 300 PM EST Sat Mar 9 2019 - Freezing rain central lower Michigan this evening - Windy late this afternoon through tonight into Sunday - Some light snow showers late tonight and Sunday - Milder with rain showers Wednesday through Thursday && .UPDATE... Issued at 1022 PM EST Sat Mar 9 2019 Based on recent trends in wind and weather we added Oceana and Mason. A variety of precipitation types along with gusts over 40 knots support the headline. Some impacts also noted on the roads. UPDATE Issued at 843 PM EST Sat Mar 9 2019 We added a few more counties to the winter weather advisory. This was based on temperatures being at or below freezing and rounds of precipitation moving through. Radar does show another round of steady to heavy precipitation tracking towards these conditions will likely worsen over the next hour or two. We have been highlighting the wind impacts much of the evening. Gusts have generally been 35 to 45 throughout the area and this has caused some power outages. It looks like there will be a lull in the wind starting in an hr or two the will last for a few hours. Then the wind will shift to the southwest and increase considerably again after midnight. Winds of 35 to 45 mph are expected. Thus...scattered power outages are possible again late tonight into Sunday. && .DISCUSSION...(This evening through next Saturday) Issued at 300 PM EST Sat Mar 9 2019 Main short term fcst concerns continue to involve assessment of freezing rain potential north of I-96 this evening. A strong low pressure system near Kansas City early this afternoon will move northeast and bring rain into our southern fcst area late this afternoon and evening. A consensus of latest high resolution model guidance such as the nam nest and hrrr continue to show potential for several hours of freezing rain over roughly the northeast 6 counties in our fcst area where the winter wx advisory is in effect. The winter wx advisory headline looks excellent and will remain unchanged for up to around a tenth of an inch of ice accumulation up there. Latest hrrr and especially the 12z nam nest guidance still show potential for more ice accumulation than that. However based on overall shorter range guidance trends the past 24 hours we believe a tenth of an inch or less of ice accumulation will be the most likely outcome up there and this notion is more in line with latest runs of the hrrr. 12Z HREF ensembles suggest pcpn could even begin as fzra as far south as KMKG/KGRR/KLAN. Based on overall guidance trends and current sfc obs this is too far south (unless if wet bulb/dynamical cooling effects when rain initially moves in this evening causes the sfc temp to drop to 32 F). It is noted that dew point values along the I-96 corridor are only in the teens as of mid aftn. Our gut feel is that sfc temps will stay above freezing in the middle 30s in the GR metro area this evening before actually going up a few degrees late tonight before fropa. This strong low pressure system will bring windy conditions late this afternoon through tonight into Sunday. Peak wind gusts may flirt with advisory criteria at a few locations (especially near the Lake MI shoreline) this evening and overnight. However for the most part we expect gusts predominantly in the 30 to 44 mph range. Therefore we will not issue a wind advisory headline. Rain showers will change over to snow showers late tonight as caa commences on the back side of the low. However any snow accumulations late tonight through tomorrow will be very light at only around an inch or less (relatively highest accumulations in that range over our northern fcst area). Tranquil wx is fcst Monday through Tuesday as a high pressure ridge builds in from the west. Strong waa will develop on the back side of the departing ridge for midweek and rain showers are forecast Wednesday through Thursday. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 636 PM EST Sat Mar 9 2019 Gusty wind impacts will continue at the TAF sites for much of the period with values topping 30 knots at times with local 40 knots possible. The direction will be shifting from east to southeast then southwest to more of a westerly wind through the period as well. Visibility and ceiling impacts are likely as well with moisture on the increase and rain moving in. The onset of the precipitation is close to being a wintry mix...but at this time it looks like it will be plain rain for the TAF sites. IFR is expected at times with an increased risk for sub IFR. Some instability lifting northeastward from Indiana may support an isolated thunderstorm or two...mainly over far southern Lower Michigan this evening. As temperatures fall late tonight into Sunday morning any remaining precipitation is expected to transition into snow. && .HYDROLOGY... Issued at 300 PM EST Sat Mar 9 2019 Rain and freezing rain will spread into the area this evening and last through the overnight hours before changing to light snow Sunday morning. Total rain and water equivalent from the ice and snow that will fall looks to average around three-quarters of an inch. Rain may even be heavy at times. Rain and warmer temperatures will melt some of the snowpack, especially for areas near and south of I-96. Runoff from precipitation and snowmelt will cause significant rises on rivers and streams, starting with the smaller ones this weekend, with the larger rivers following next next week. The most notable rises are expected to occur within the Grand River Basin, and many rivers and streams there are forecast to reach bankfull. A few could just touch minor flood stage (Looking Glass near Eagle, Grand River near Robinson Township) and will need to be watched closely. Additional precipitation is expected Wednesday night and Thursday, but has not yet been accounted for in current river forecasts. Although amounts look much lighter with this second system, much warmer temperatures are expected which will melt much, and in some places all, of the snow left on the ground. This could prolong or add to rises in rivers already occuring due to precipitation this weekend. Finally, ice remains intact along stretches of rivers in West Michigan. Warmer temperatures and increased runoff may shift or break this ice up, leading to rapid changes in water levels or even a few break-up ice jams. If you live along a river, be alert for changing conditions and rising water levels. && .GRR WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 1 AM EST Sunday for MIZ037>040- 043>046-051-052. && $$ UPDATE...MJS SYNOPSIS...Laurens DISCUSSION...Laurens AVIATION...MJS HYDROLOGY...HLO
Area Forecast Discussion
National Weather Service Jacksonville FL
858 PM EST Sat Mar 9 2019 .UPDATE... Warm southerly flow continues over the forecast area this evening with fairly strong low pressure system at 991 mb over IL with trailing cold front through the Mid MS valley into ern TX. Locally, temps are in the 60s and 70s at 8 pm and with occasional clouds tonight and with prevailing low level flow from the south, lows not expected to drop lower than about 58-60 deg tonight. Some patchy fog is possible but given the low level weak boundary layer mixing and occasional clouds, not the optimal setup for some fog formation. Some stratus and fog may form near the coast where relatively warm/moist air overrides the cooler Atlantic shelf waters, so will maintain patchy fog and some stratus for the coastal areas overnight and into Sunday morning. Otherwise, little change for the evening update. && .AVIATION... VFR cig conditions will prevail most of tonight and Sunday. A brief period of MVFR cig/vsby possible from 06z to 13z. HRRR and SREF also suggest some lower cig conditions to IFR/LIFR at SSI late tonight and early Sunday due to some potential for sea fog off the Atlantic waters, so will be monitored. Stratus and any mist/fog will dissipate Sunday morning with VFR conditions after 13z-15z. && .MARINE... South-Southeast winds near 10-15 kt will gradually veer to south and decreasing a few knots by 12z Sunday. The increased winds may kick up wind waves a bit for tonight. A slight decrease in winds around 12z may enable some patchy sea fog to form along the coast by early Sunday morning. Will keep this in the forecast at this time. && .PRELIMINARY POINT TEMPS/POPS... AMG 61 83 62 78 / 0 20 30 20 SSI 62 77 62 75 / 0 0 20 20 JAX 63 83 62 81 / 0 0 10 40 SGJ 65 81 62 80 / 0 0 10 30 GNV 63 85 61 84 / 0 0 0 30 OCF 63 85 61 85 / 10 0 0 10 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$ Shashy/Peterson
Area Forecast Discussion
National Weather Service Elko NV
202 PM PST Sat Mar 9 2019 .SYNOPSIS... A storm system will bring accumulating snow to parts of central Nevada tonight through Sunday but should stay mainly south of Interstate 80. Snow showers will taper off Sunday night as the weather disturbance moves farther away from the region. Another cold front will bring more snow to the state Tuesday into Wednesday before drier conditions finally settle in for the latter part of the week. && .SHORT TERM...Tonight through Tuesday. Mid-level low pressure system will slide southeastward along the CA coast through Sunday. A diffuse boundary across central Nevada along with the CA low will regenerate snow across central Nevada tonight into Sunday. Central Nevada including southern Lander and Eureka counties, far northern Nye county and White Pine county are still expected to see advisory level snowfall. 3 to 5 inches should be common in WHite Pine County with slightly lesser amounts further west. In addition, the northern extent of the snow band has trended northward closer to I-80 in the latest mesoscale model runs. The HRRR, NAM and RAP all show another round of snow reaching into southwest Elko Sunday morning. Although more snow is expected across southern ELko county, only about an inch is anticipated through the late morning hours before snow diminishes along the I-80 corridor. As the low pivots into Baja California, precipitation will diminish and dissipate across central NV Sunday night and Monday. Monday night into Tuesday morning still appear dry with yet another cold front and trough moving through the state Tuesday and Tuesday night. .LONG TERM...Tuesday night through next Saturday. Cold front continues to make its way through Nevada on Tuesday night and will be east of the area by Wednesday morning. 1-3 inches of snow may fall in the valleys and the mountains of northern Elko County could see 4-8 inches by the time the storm exits. Breezy to windy northwest winds immediately follow the front as a longwave trof digs into the central U.S. and gradients tighten in our area. The winds will continue into Wednesday before diminishing on Wednesday night. Otherwise, there will just be some leftover snow showers hanging around through Wednesday evening. We will then likely transition into a cool and dry northerly flow through at least Thursday. Ridging then attempts to build in starting Friday, ushering in a long awaited period of drier weather along with a warming trend. && .AVIATION...Scattered snow showers continue in northern and central Nevada through the evening, but for the most part VFR conditions should hold at all stations through tonight. The exception will be at KELY, where a period of snow showers could bring some tempo IFR conditions later this evening. Steadier snow is expected to arrive there early Sunday morning and KTPH will also see some showers begin early in the morning. NOTE: KELY is AMD NOT SKED due to problems with visibility and weather sensors. && .LKN WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 11 PM PDT Sunday for White Pine County. Winter Weather Advisory from 10 PM PST this evening to 11 PM PDT Sunday for Northeastern Nye County-Northwestern Nye County- Southern Lander County and Southern Eureka County. && $$ 93/90/90
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
851 PM CST Sat Mar 9 2019 .UPDATE... 851 PM CST Have expanded the wind advisory across to include the northern tier of counties as well. RAP, NMM, and HRRR bufkit soundings overnight show winds as strong, if not stronger, for KRFD as points farther south in the advisory. Over the past couple hours the number of advisory level gusts at upstream sites has decreased, but still seeing occasional gusts to advisory level. Certainly would expect 40 mph gusts CWA wide overnight with at least scattered sporadic gusts of 45+ mph. - Izzi && .SHORT TERM... 212 PM CST Through Sunday... Mild, wet, and breezy conditions are expected through the rest of today, then conditions will turn windy and colder Sunday. Early this afternoon, a 992mb low is analyzed east of Kansas City with a warm front draped east across central Illinois and along portions of the Ohio Valley. Meanwhile, water vapor imagery reveals a negatively tilted trough lifting across northern Missouri. These features are progged to lift northeast across northern Illinois this evening. Rain, along with a few embedded thunderstorms, have already overspread much of the forecast area this afternoon. Periods of steady rain, at times moderate to heavy, will persist well into the evening until the warm front begins to lift across the region. Loss of deeper moisture should allow precip to taper off with a few spotty showers possible behind the warm front. Center of low pressure is expected to lift into far southeast Wisconsin late this evening, then continue northeast across the central Great Lakes region overnight. While precip chances diminish in the wake of the low, winds are expected to swing around to the west and further increase overnight. The combination of a strong pressure gradient, steep low level lapse rates driven by cold air advection, and moderately strong surface pressure rises sweeping across the forecast area will result in wind gusts right around advisory criteria of 45 mph. Both the GFS and NAM advertise 5- 7mb/3hr pressure rises moving across the CWA overnight, though weakening as it spreads east. Will be issuing a Wind Advisory through Sunday morning for all but the far northern tier of counties in Illinois, closest to the low track where the gradient is not quite as strong. Breezy conditions will persist through the day Sunday, though should very gradually taper in magnitude as high pressure spreads from the northern Great Plains to the Ohio Valley. Persistent cold advection will only allow temperatures to recover a few degrees Sunday afternoon with highs in the mid to upper 30s expected over most of the CWA. Shallow post frontal cold air stratocumulus will keep skies mostly cloudy through the day, with some clearing possible during the evening. Temperatures are expected to fall into the low to mid 20s Sunday night with wind chills in the single digits and teens. Deubelbeiss && .LONG TERM... 116 PM CST Sunday night through Saturday... High pressure will usher a frontal trough Sunday night. There is a weak disturbance in northwest flow aloft that still looks just produce some clouds when it arrives Sunday night into early Monday. The surface high will arrive Monday into Tuesday, leading to a period of dry but cool weather. The high will shift east of the area late Tuesday and again open the door to another amplified pacific system emanating from the southwest. Deep layer flow will become markedly southerly ahead of the highly meridional flow across the Midwest and eastern portions of the United States as, at least for a time, several systems merge into a large scale trough across the western half of the country. With upstream ridging in place, the model evolution becomes a bit more tricky as to how quickly precipitation will push into the departing ridge. But it appears the fairly wound up lead system will send several shortwaves ahead of it and lead to mild, windy, and occasionally wet periods later Tuesday into Thursday. The main surface low will approach the region Thursday into Friday, weakening as it will move from the Mississippi valley to northern Lake Michigan. With this pattern, it appears we get somewhat split with the system dry slot possibly moving right overhead and the heavier precip will head south. With the dry slot moving in and warm southerly flow, temperatures could briefly get quite mild Thursday morning The northern stream flow will eventually win out late week, sending a cold front through Thursday afternoon/evening and possibly even leading to some snow showers. KMD && .AVIATION... For the 00Z TAFs... The main forecast concerns through the period are: 1.) the threat of a few embedded thunderstorms through around 01z over the eastern terminals. 2.) CIG and VSBY trends through the evening, with IFR conditions likely, possibly lowest at KRFD. 3.) Strong gusty easterly winds this evening, with veering winds this evening before becoming very gusty from the west overnight and continuing on Sunday. A potent area of low pressure will track northeastward across north central IL early this evening before shifting into Lower Michigan overnight. Periods of showers, with a few embedded storms will be possible this evening, with the primary thunder threat just through 01z. Also expect gusty easterly winds to gradually swing to the south-southeast mid to late this evening. Visibilities will be down into the 1-2 mile range, especially early this evening. However, with the track of the surface low going right over the RFD area, they could experience a short 1 to 3 hour period of low visibilities down around 1/2 a mile before the low shifts to the northeast. Overnight, expect strong west-southwesterly winds to develop, especially after 06-07z. A period of gusts up to around 40 kt is possible with the initial onset of the westerly winds. However, wind gusts may begin to settle down to around 30 kt during the day on Sunday. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...Wind Advisory...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011- ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023- ILZ032-ILZ033-ILZ039 until 7 AM Sunday. IN...Wind Advisory...INZ001-INZ002-INZ010-INZ011-INZ019 until 7 AM Sunday. LM...Gale Warning...nearshore waters until 4 PM Sunday. Small Craft Advisory...nearshore waters until 11 PM Saturday. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1016 PM EST Sat Mar 9 2019 .SYNOPSIS... A warm front will lift north through the area tonight. A cold front will approach from the west Sunday and cross the area Sunday night. High pressure will build in from the northwest early next week and slide offshore by mid week. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... As of 1010 PM Saturday...The warm frontal boundary continue to lift north and is approaching our south coast at late evening as high pressure off the northern New England coast slowly retreats offshore. Some light showers are offshore with additional showers well north and west of the CWA. The latest HRRR and 3km NAM continue to trend fairly dry overnight and will keep the existing low PoPs in the forecast overnight to account for some light showers that could sneak into the area from off the water or from the west. Temperatures have likely reached their low for the night and should start to slowly rise as the warm front lifts north. No major changes made to the current forecast. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... As of 2 PM Sat...Deep low pressure will continue to lift through the Great Lakes region as attendant cold front approaches Eastern NC from the west. Eastern NC will be in the warm sector and SPC continues to outlook most of the area in a Marginal Risk for severe weather. 12z guidance has continued to trend like previous guidance depicting a drier solution across the area. Latest global, high res and ensemble guidance show pretty good instability (MU CAPE values around 1000 J/kg) developing across the area Sun afternoon and bulk shear 30-40 kt. Best forcing will remain north of the area but could be just enough convergence combined with instability to generate scattered convection. At this point moisture looks like the only limiting factor. Some strong to severe storms with gusty to possibly damaging winds will be possible during the afternoon and evening hours. Very warm day expected with temps well above normal despite the cloud cover. Low level thickness values and SW flow support highs in the upper 60s to low 70s along the coast, and mid to upper 70s inland. Some guidance shows the potential for sea fog developing during the day, but feel this is likely overdone at this point but not out of the question. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... As of 310 PM Sat...The front will gradually push offshore with lingering showers Monday morning before conditions dry out as high pressure dominates the region. Another cold front is expected to approach the area at the end of the work week. Sunday night through Monday...As the cold front approaches ENC, upper level support becomes marginally better behind the front as a subtle shortwave approaches during the overnight hours. This will allow for shower coverage and intensity to increase Sunday night. Gradually increased PoPs to high chance/likely for the tidewater and coastal zones with the highest chances between 00-06Z. Any severe threat will be diminished by this point but with lingering marginal instability kept the mention of isolated thunderstorms through 06z Monday; mostly along the coastal areas. The front is forecast to be offshore by Monday morning with a few lingering showers possible along the southern coast. High pressure will build in from the NW...providing drier conditions by Monday afternoon. Highs Monday around the mid to upper 60s with lows falling into the low 40s as a dry front pushes across Monday night. Tuesday to Friday...Upper level ridging gradually amplifies into Thursday with high pressure dominating through most of this period. Temperatures will slightly be below normal Tuesday and Wednesday with highs upper 40s NE to around 60 SW. Highs climb back into the 60s NE to around 70 SW Thursday and then low to mid 70s as southerly flow ahead of another approaching cold front. The 12Z GFS/ECMWF are in decent agreement regarding timing of FROPA and precipitation but will go no higher than chance PoPs for now. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... Short Term /through 00Z Monday/... As of 7 PM Saturday...With the exception of some lower ceilings around KPGV, TAF sites are currently in the VFR range. Tricky forecast for this TAF cycle. Most guidance shows a period of solid MVFR ceilings for all TAF sites after midnight and will follow this trend, however lack of any precipitation to moisten the low-levels may prevent ceilings from lowering quite as dramatically as guidance is showing. Any low ceilings should lift after 13z-14z as mixing improves with warm front moving north of the area. Most of the high-resolution models show the bulk of any showers or psbl tstms holding off until after 00z and have left shower/tstm mention out of the TAFs at this time. Long Term /Sunday night through Thursday/... As of 305 PM Sat...Sub-VFR conditions may linger through Monday morning before VFR conditions return by afternoon. VFR conditions will dominate through Thursday. && .MARINE... Short Term /through Sunday/... As of 1015 PM Saturday...Winds continue NE/E at 5-15 knots on area waters at late evening with seas 3-4 feet. The warm front is starting to move into the far southern waters and will continue to lift north overnight. As a result, winds become SE/S 10-20 kt late tonight and early Sun. The warm front will be north of the waters by Sunday morning as cold front approaches from the west during the day. SW winds will increase to 15-25 kt Sun. Went ahead with a SCA for the waters south of Oregon Inlet and the Pamlico Sound for the increasing SW winds developing ahead of the front Sunday afternoon into Sunday night. Seas will build to 4-6 ft late Sun afternoon and evening. Long Term /Sunday night through Thursday/... As of 305 PM Sat...Conditions are expected to improve Monday after the cold front pushes through the coastal waters with seas diminishing to 3-4 feet and winds becoming NW/N at 10 knots or less. A dry cold front pushes through late Monday into Tuesday with N wind increasing to 15-20 knots with possible gusts to 25 knots and seas 4-6 feet especially for nrn and cntrl waters. Seas are expected to subside subside to 2-4 feet Wednesday and Thursday as winds diminish to 10-15 knots from the NE/ENE, then veering to the S Thursday. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...Small Craft Advisory from 2 PM Sunday to 2 AM EDT Monday for AMZ152-154. Small Craft Advisory from 2 PM to 11 PM EDT Sunday for AMZ135- 156-158. && $$ SYNOPSIS...MHX NEAR TERM...CTC SHORT TERM...CQD LONG TERM...BM/MS AVIATION...CTC/CQD/MS MARINE...CTC/CQD/MS
Area Forecast Discussion
National Weather Service Marquette MI
633 PM EST Sat Mar 9 2019 .SHORT TERM...(This evening through Sunday) Issued at 424 PM EST SAT MAR 9 2019 Water vapor imagery and RAP analysis show a vigorous, negatively tilted shortwave lifting ne into the Mid-Mississippi Valley this aftn. Diffluent flow aloft, strong dynamics and abundant moisture (precipitable water running up to 200-250pct of normal thru the southern/central Plains per 12z raobs) are supporting a large swath of pcpn up the Mississippi Valley into the Ohio Valley. Pcpn is spread across sw WI as of 21z. At the sfc, 990mb sfc low was located over nw MO. Shortwave will swing ne into the western Great Lakes region by 12z Sun and then continue into Ontario during the day as it weakens. Strong isentropic ascent/deep layer forcing/upper diffluence will quickly spread ne across the area tonight, but strongest forcing is fcst to occur to the s and sw of Upper MI with a weakening trend evident as the forcing lifts ne into the fcst area. As a result, pcpn is likely to be diminishing in intensity as it moves across Upper MI. There is still some potential of mid-level dry slotting to occur late tonight/Sun morning over the se/e fcst area, but there is not a solid signal in all the guidance. Opted to maintain previous fcst mention of chc -fzra in that area due to the potential of a reduction in ice nuclei from the dry slotting. Mixing ratios of 3- 4g/kg are available per 290-295k sfcs (roughly 700-750mb), suggesting snowfall of 3-4in/6hr, which is about how long the isentropic ascent portion of the event lasts tonight. Cyclonic n backing nw low-level flow and lingering deep layer forcing Sun morning will support some additional snowfall during the morning, especially across the higher terrain of western and northern Upper MI favored by the backing, upslope winds. 850mb temps around -8C on Sun are marginally cold enough for lake enhancement, but considerable ice cover on Lake Superior will significantly diminish the lake enhanced component to the snowfall over what it could be. Lingering snow across the w and n will diminish Sun aftn. However, another shortwave will streak from the Dakotas to nw WI by 00z Mon. This wave should give a boost to the snow over the w during the latter portion of the aftn. Winds will become gusty out the nw to w during the day on Sun as the low departs. Weak CAA and a lack of an isallobaric component to the wind will help to keep winds in check. Still, expect gusts to 25-35mph Sun aftn, leading to some drsn/blsn. As for snow amounts, should see a widespread 3-5in snowfall across the area by late Sun morning with a few spots perhaps reaching 6in. Boosted by an upslope e backing ne wind overnight, the high terrain of Marquette County w of Marquette probably has the best potential of seeing amounts up around 6in. During Sun aftn, another 1-2 inches of snow may accumulate e of Munising and also over western Upper MI. Fcst snow amounts are still blo the low snow-to-water ratio snowfall criteria for a warning (at least 6in/12hr or 8in/24hr), so no headline changes from current advy are needed. Since this will be a wet/heavier snow, it will be more difficult to shovel/plow, and of course, wet snow makes travel conditions more hazardous than high snow-to-water ratio snow. .LONG TERM...(Sunday night through Saturday) Issued at 340 PM EST SAT MAR 9 2019 As a lobe of vorticity and a surface trough move through early Sun night, could see 1-3" of snow in areas favored by NW wind upslope (Keweenaw, Huron Mountains, And NE Upper MI). Snow quickly tapers off by later Sun night. Some blowing snow is expected near Lake Superior Sun night into Mon. Attention then turns to Tue night into Thu night when warm, moist air surges into the region ahead of a strong low pressure system. Ptype is troublesome Tue night as surface temperatures start out below freezing, resulting in some freezing rain, but temperatures will be warming so the threat will not be overly persistent. Temperatures will top out in the 40s Wed and Thu with lows Wed night above freezing. Dew points will also be above freezing. Rain is expected more often than not during the period, with potential for 1- 2" of liquid. Uncertain on exactly how much runoff into streams will occur, but at this point expecting the snow pack to soak much of the precip up. Certainly could see some issues with ponding on water on roads, though. Precip turns to snow Thu night and Fri as the rapidly weakening low shifts across the area. Plenty of uncertainty in how much snow falls, but not looking like anything too significant at this point. Colder temps Fri into the weekend will, for the most part, put a halt to the melt, leaving us with even more liquid in the very compressed snow pack. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 633 PM EST SAT MAR 9 2019 VFR conditions will prevail into the early evening at KIWD/KCMX/KSAW. Approaching low pres system will then spread snow from sw to ne tonight. Conditions at all terminals will deteriorate quickly to at least IFR once the snow begins. A period of LIFR is certainly possible overnight. Improvement to MVFR should occur late Sun morning or early aftn. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 424 PM EST SAT MAR 9 2019 Low pres currently over nw MO will track to far eastern Upper MI Sun morning, and then into Ontario Sun aftn. As it approaches, easterly winds will increase to 20-30kt across across Lake Superior tonight. Not out of the question that there could be a few gale force gusts. On Sun, winds will back around to the nw to w, and gales to 35kt should develop over the e half of the lake for the aftn into the early evening. Winds will only slowly diminish from w to e Sun night/Mon, leading to a period of lighter winds under 20kt Mon night/Tue. Winds will increase again midweek, but gales are not anticipated at this time. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Winter Weather Advisory until 5 PM EDT Sunday for MIZ001-003>007- 013-014-084-085. Winter Weather Advisory until 5 PM EDT /4 PM CDT/ Sunday for MIZ002-009. Winter Weather Advisory until 1 PM CDT Sunday for MIZ010>012. Lake Superior... Gale Warning from 2 PM to 10 PM EDT Sunday for LSZ248>251- 265>267. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...Titus AVIATION...Voss MARINE...Rolfson
Area Forecast Discussion
National Weather Service Reno NV
157 PM PST Sat Mar 9 2019 .SYNOPSIS... A couple colder storms will impact the region. The first tonight into Sunday will bring snow showers with light accumulations to many areas. A second fast moving cold front will bring light snow and strong winds Tuesday. The balance of the week into the following week looks dry with gradually warming temperatures, heralding the much anticipated start of spring in the region. && .DISCUSSION... Through Monday... Ah, nothing like another clear cut storm headed our way... * Low pressure off the N California coastline will bring periods of snow showers to the Sierra and Western Nevada this evening through Sunday. Problem is potential for banding/stalling that could yield bigger snow amounts and impacts in localized areas. No radical changes to the forecast, just a few tweaks to snow totals through Sunday. * Heavily weighted forecast on 12z/18z HRRR which shows most areas, mountain and valley, getting light snow showers tonight into Sunday morning. High-res models indicate banded areas of snow over W Nevada that more or less stall as steering flow turns from southerly to easterly late tonight. Each run has a different spot but a few have been over the Reno and Carson City area, perhaps just to the northeast near Pyramid Lake. * For the Sierra tonight into Sunday morning, a 8/10 chance of seeing at least a dusting, with a 6/10 chance of 1-3" in mountain communities. For Western Nevada, let`s say a 7/10 chance of seeing at least a dusting of snow accumulation tonight into Sunday morning with a 4/10 chance of ~1" and a 2/10 chance of 3" or more. Just to convey the confidence a little differently. * From an impact standpoint with temperatures expected to fall below freezing, any new snow will stick to untreated roads. So even an inch or less could have meaningful travel impacts overnight into Sunday morning. Predictability with this storm is low with hit and miss snow amounts. That plus with typical low- traffic volumes Saturday night into Sunday morning so have opted to pass on a winter weather advisory. * Into Sunday afternoon and evening instability driven snow showers will persist, however with March sun energy and temps warming above freezing road impacts should be low. Eastern Sierra probably has their best snow coverage then as low pressure continues dropping south. Sunday evening has some concern with models showing snow showers continuing coupled with cooling temps, so travel impacts may return then. -Chris Tuesday Onward... Other then lowering min temps a few degrees later next week, we didn`t change much for the extended period. For Tuesday, model guidance remains consistent with a trough passage producing a round of light snow over eastern CA-western NV. This snow looks to start north of Portola-Gerlach during the morning, then spread quickly southeast to near US-50 during the afternoon, and south of US-50 by early evening. Overall forcing looks relatively weak, with model soundings only showing moisture depth up to 550-600 mb, resulting in snowfall rates too light to produce much accumulation. Overall snow amounts are expected to be 1" or less, except for parts of northeast CA, the eastern Sierra and the central NV mountains east of US-95 which could receive 1-3". However, with much of this snow falling during the daytime, even these modest accumulations are likely to be limited to unpaved surfaces. As a result, overall travel impacts for lower elevations don`t look to be very hazardous Tuesday evening. With sunset occurring after 7 pm due to the PDT time change, roads should remain wet through the peak evening commute. In addition, brisk northwest winds behind this system should increase the drying rate of road surfaces before temperatures fall below freezing. If any icy patches develop, this is more likely late Tuesday night into early Wednesday morning, and in areas south of US-50 where the window for drying will be shorter. For the Sierra/Tahoe regions and northeast CA west of Susanville, untreated roads could remain slick with a minor accumulation of snow Tuesday evening into Wednesday morning. On Wednesday as the trough exits to the east, brisk northwest winds and chilly temperatures are expected, with highs only in the lower- mid 40s for lower elevations and 30s near the Sierra, about 10-15 degrees below average. A few very light non- accumulating snow showers remain possible for parts of west central NV mainly from US-95 eastward. From Thursday into next weekend, the medium range guidance favors ridging over CA-NV, allowing for a dry weather pattern and slowly warming daytime temperatures, although nights should remain cool with overall light winds and limited cloud cover. A few scenarios attempt to weaken the ridge with either a weak shortwave passage, or an upper level disturbance slipping under the ridge axis, but this would only bring some increase in cloud cover with no precip. MJD && .AVIATION... Low pressure off the N California coastline will bring periods of snow showers to the Sierra and Western Nevada this evening through Sunday. Heavily based latest forecast on HRRR and GFS runs. For TRK,TVL: High confidence in seeing some light snow accumulation and MVFR/IFR conditions this evening into Sunday morning. Some wind shear issues are possible through this afternoon into early evening with mountain ridges currently gusting above 50 mph. For RNO,CXP: Much lower forecast confidence for W Nevada as models are showing heavier snow pockets, but at varying locations from run to run. Figuring we`ll see at least a period of light snow late this evening into early Sunday morning with 40% chance of light runway accumulations as air temps drop below freezing. This could impact late evening and early morning peak traffic. If banded snow stalls over the region, can`t rule out 2" or more but confidence is low in this scenario. Sunday mid-morning onward should see improving conditions during day time with more showery precip and sun energy melting pavement. For MMH: Pretty much left out of this initial storm with precipitation from Central California breaking apart by the time it reaches the Eastern Sierra, per the HRRR. Main snow accumulation and reduced flight category issues at MMH may end up being Sunday afternoon-evening with instability snow showers. -Chris && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$ For more information from the National Weather Service visit...