Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/05/17

Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
550 PM MDT Tue Apr 4 2017 .UPDATE... Updated forecast to cancel winter highlights and decrease 1st period PoPs/QFP and snow amounts given latest radar and HRRR model trends. Otherwise, forecast on track. 11 && .PREV DISCUSSION...540 PM MDT Tue Apr 4 2017... .AVIATION... 00Z TAF CYCLE Aviation impacts tapering off this evening as the upper wave pulls well east into the Great Plains. A band of -SHRA/SN over the northern high terrain will dissipate thru 04Z, but not before producing some brief MVFR cigs/vsby restrictions for KLVS. Otherwise, clearing from west to east overnight with very dry and cold conditions. A few high clouds will spread over NM Wednesday with overall light winds. Guyer && .PREV DISCUSSION...311 PM MDT Tue Apr 4 2017... .SYNOPSIS... The Pacific storm system will exit to the east early this evening, with winds and precipitation gradually diminishing. Areas of snow will persist early this evening across north central New Mexico, where a few inches of additional accumulation are possible. A warming trend will begin Wednesday, with temperatures rising above normal areawide by Friday. Saturday will be windy, with above normal temperatures persisting ahead of an approaching Pacific cold front. Windy to very windy conditions will prevail Sunday both ahead of and behind the cold front. Temperatures will dip below normal behind the front briefly before warming back up early next week. && .DISCUSSION... The upper low is currently pulling east into the Texas Panhandle per the latest water vapor satellite imagery, with areas of wrap-around precipitation persisting across north central and eastern New Mexico. Surface temperatures are currently several degrees above freezing behind the backdoor portion of the cold front across northeast New Mexico and precipitation is diminishing there, so will cancel the winter storm warning for portions of the Northeast Plains/Highlands. The latest NAM and HRRR develop more precipitation over the Tusas/Jemez Mountains early this evening and then spread it east across the Upper Rio Grande Valley into the Sangres, so will hold onto the winter weather highlights for those zones for now. Will also cancel portions of the wind advisory and high wind warning given current observations below thresholds and placement of the backdoor front. A cold night is on tap, with lows below normal and a number of lower elevation locales forecast to experience a solid freeze. A long wave ridge, currently progressing east from the west coast, will transition across the Intermountain West the next couple of days and lead to a warming trend that will send temperatures above normal areawide by Friday. Afternoon breezes will develop by Friday, but winds will really ramp-up over the weekend as a trough and attendant Pacific cold front progress east into the Rockies. New Mexico will remain at the base of the trough, so the main impacts will be wind and fire weather related. Saturday is looking windy with above normal temperatures persisting given the timing of the frontal passage sometime Sunday. Very windy conditions are likely Sunday both ahead of and behind the cold front. Look for cooling behind the front to send temperatures below normal briefly, prior to a warm-up early next week. 11 && .FIRE WEATHER... The upper low which brought widespread rain and snow to much of New Mexico today is lifting east-northeast into the Texas panhandle this afternoon. Strong northwest and north winds on the backside of the low will subside early this evening. Drier and warmer condtions remain on track for Wednesday as dry northwest flow aloft moves overhead. High temperatures will remain around 5 to 10 degrees below average levels for the date. Models remain in very good agreement for Thursday and Friday. An upper level ridge moves overhead Thursday, then shift east of the region Friday. West and southwest winds increase Friday afternoon. Models continue to bring up a weak subtropical wave from the southwest Thursday night and Friday. This feature is expected to result in an increase in mid and high clouds and not much else. Winds increase further over the weekend with an upper level trough/closed low moving eastward through the northern and central Rockies. A few showers may graze the northern mountains but increasing wind expected to be the main impact. Areas of critical fire weather conditions will likely develop across much of the area primarily Sunday afternoon. Ventilation rates increase markedly Friday, remaining very good to excellent through the weekend. 33 && .ABQ WATCHES/WARNINGS/ADVISORIES... None. && $$ 11
Area Forecast Discussion
National Weather Service Caribou ME
937 PM EDT Tue Apr 4 2017 .SYNOPSIS... Low pressure will track south of the Gulf of Maine tonight. The low will continue east into the open Atlantic on Wednesday. Weak high pressure builds Wednesday into early Thursday. An occluded front will cross the region Thursday night. && .NEAR TERM /THROUGH WEDNESDAY/... 930 PM Update. Updated POP and WX grids to reflect current and expected conditions, used HRRR which seems to have a good handle on current conditions. Minor adjustments to HRLY temps. .Previous discussion... A very complex situation unfolds this evening and tonight. A weakening shortwave is crossing the state now with some rain and snow. This shortwave is weakening as it moves into a blocking upper ridge over Eastern Canada. A somewhat vigorous and compact upper low that is sparking some thunderstorm activity will move out of upstate New York towards the Gulf of Maine later tonight. Cyclogenesis will occur ahead of this upper low off Cape Cod. This new surface low will move under the blocking upper ridge towards a position south of Nova Scotia by Wednesday morning. Meanwhile the original low pressure system in Ontario will drift into Quebec and fill as it moves into the blocking ridge. The net result is that all of the energy in this pattern will be with the developing offshore low. The heaviest precipitation with this low will be southwest of the forecast area this evening, but affect an axis from southern Piscataquis County southeastward towards the Bangor area and Hancock County after midnight. By this time, boundary layer temperatures will have cooled towards the freezing mark and precipitation should be all snow. In terms of snowfall, these areas could see as much as 2 to 4 inches of snow after midnight into early Wednesday morning when the axis pulls out. Will have to closely monitor the situation for a possible expansion of current winter weather advisories. Elsewhere, the influence of the blocking high has led to a reduction in snowfall forecasts along the eastern border of the state where an inch or less will fall by Wednesday morning. The low will slide away by Wednesday morning and strong subsidence is expected to keep low clouds in the forecast area through the day. Northern zones may see a few light rain and snow showers as the remnants of the upper trough moving up the blocking ridge crosses. The cloud cover will limit Wednesday`s highs to the upper 30s to near 40F. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... Any lingering showers quickly dissipate Wed night, but increasing POPs expected across the CWA from 12z Thu onward as the next system pushes into the region. The 12z CMC shows a weak sfc low moving west across the Gulf of Maine and getting absorbed into the larger system Thu, bringing precip to the southern CWA before 12z. However, this appears to be an anomaly and was largely discounted. The short term POPs were mostly a blend of the GFS, NAM, and ECMWF, all of which show a roughly similar evolution of the system and track of the sfc low. This sfc low actually looks to hang back over NY or Lake Ontario, while the occlusion triple point moves over Maine. Wx grids are a bit messy Thu night into Fri, as there are hints across a couple models that some warm air may overrun a subfreezing layer at or just above the sfc. This could allow for some sleet or even freezing rain at times before the entire lower part of the column gets above freezing during the day Fri. Highs will be near to below normal for Thu, and near normal Fri. Winds will be E-SE Wed night into Thu night, turning more SE-S Fri as the triple point lifts north of the CWA. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Rain and snow showers will likely linger over the area Fri night into Sat as the sfc trough that had been hanging back over NY and southern Quebec finally swings across the area, concurrent with the passage of the upr trof. Once these features pass between 18z Sat and 00z Sun, POPs drop off significantly, and dry weather with party to mostly clear skies are expected Sun and Mon. There are hints that some weak sfc feature may bring some precip to the CWA between Mon night and Tue night, but models don`t show very strong upper level support, so POPs were kept under 50 pct for now. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... NEAR TERM: A brief period of IFR is possible in snow north of HUL this evening and tonight, but it will be VFR otherwise. For southern sites such as BHB and BGR, conditions will deteriorate to IFR this evening in snow and become LIFR for a period of several hours late tonight. The snow will end towards daybreak and conditions will improve to MVFR cigs at these sites. SHORT TERM: Wld expect VFR vsbys for all terminals Wed night and Thu AM, but some lingering low-lvl moisture could keep some patchy MVFR or IFR CIGs across the region during that time. CIGs and vsbys both drop to widespread IFR and patchy LIFR Thu PM thru Fri AM as the next system moves thru, with mostly rain for Downeast, while KHUL to KFVE could have mix with or change to snow Thu night. Lingering MVFR to IFR conditions possible for KHUL northward on Sat, with MVFR or VFR more likely down south. All sites should clear to VFR Sat night into Sun. && .MARINE... NEAR TERM: Have held to a strong SCA tonight with a few gusts to 35 kts referenced rather than an upgrade to a gale warning. Did extend the SCA another three hours to 2pm Wednesday as winds will take longer to decrease. SHORT TERM: Gentle E-SE`ly winds and seas under 5 ft expected Wed night into Thu, before winds and seas both increase above SCA criteria lvls Thu aftn and night. Winds lkly to drop below criteria by Fri AM, but seas could remain elevated into Fri eve. && .HYDROLOGY... Currently, NOHRSC maps show 10-20 inches of snow depth and SWE of 3-6 inches for parts of southern Piscataquis and central Penobscot. This area could also receive around an inch of rain Thu PM into Fri AM. Today`s river survey covered rivers in this area, and reports that the Piscataquis was largely ice free up to Milo. Thus, it does not appear that ice jam flooding is a major threat for this region. However, across the Northern Maine rivers, the ice jam flooding threat still remains above normal. If the QPF forecast increases, the snowmelt/runoff combination could cause issues on rivers and streams. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...Winter Weather Advisory until 8 AM EDT Wednesday for MEZ003- 004-010-031. MARINE...Small Craft Advisory until 2 PM EDT Wednesday for ANZ050>052. && $$ Near Term...Norton Short Term...Kredensor Long Term...Kredensor Aviation...Norton/Kredensor Marine...Norton/Kredensor Hydrology...Hewitt
Area Forecast Discussion
National Weather Service Dodge City KS
600 PM CDT Tue Apr 4 2017 ...Updated Aviation... .SHORT TERM...(This evening through Wednesday) Issued at 324 PM CDT Tue Apr 4 2017 More numerous shower activity redevelopment appearing in the developing warm sector across western Oklahoma, disjointed from the more mid level frontogentic forcing across the panhandles. The WRF/NMM/ARW show the advection of these rain showers northward with the mean flow, as well as additional frontogentically forced rains (if temperatures are maintained above freezing) moving through the bulk of the CWA through roughly mid-evening. In the far southwest a winter weather advisory for snow has been issued where at least an inch has already fallen near Elkhart impacting roads as seen in KDOT cams and at least a couple of more hours of precipitation will continue through late afternoon. We will need to monitor the temperature trends immediately to the north to determine if additional areas will see snow accumulation, however the models themselves were far overdoing the snow amounts, with unverified significant snow accumulations already at 21z this afternoon. At that point the forcing should begin weakening dramatically across central Kansas, as winds turn more northwesterly with time. The lower clouds will become scoured out after midnight, allowing for decent radiational cooling towards 12Z Wednesday. Looking ahead, no true cold advection develops even tomorrow under the northwest surface winds, so models bring highs in the afternoon to near 60s degrees in the lower plains. .LONG TERM...(Wednesday night through Tuesday) Issued at 324 PM CDT Tue Apr 4 2017 A gradual warming trend is expected through the middle of the weekend with dry weather at least through the end of the week. Temperatures by Saturday afternoon will reach the 80s. Another synoptic wave will bring a regime change at least in wind pattern by Sunday or Monday, with low confidence of precipitation chances at this time. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 600 PM CDT Tue Apr 4 2017 Poor flying weather will continue through about 06z, with widespread moderate rain and IFR cigs/vis. Some minor wet snow accumulations will continue on grassy surfaces at LBL. Forcing for precipitation will end rapidly tonight, with HRRR model showing rainfall become light and showery by 06z, and ending completely by 09z Wed. After 15z Wed, VFR/SKC expected at all airports. N/NW winds will remain gusty and elevated overnight, and increase further after 15z behind the departing storm system. NW wind gusts near 35 kts can be expected after 15z. && .PRELIMINARY POINT TEMPS/POPS... DDC 36 57 33 63 / 90 0 0 0 GCK 33 58 31 63 / 80 0 0 0 EHA 29 55 32 63 / 40 0 0 0 LBL 33 56 31 64 / 60 0 0 0 HYS 39 57 33 61 / 80 10 0 0 P28 42 60 34 64 / 80 10 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 9 PM CDT this evening for KSZ084- 085. && $$ SHORT TERM...Russell LONG TERM...Russell AVIATION...Turner
Area Forecast Discussion
National Weather Service Wilmington NC
943 PM EDT Tue Apr 4 2017 .SYNOPSIS... Broad high pressure off the coast will maintain seasonable warmth through Wednesday night. The approach of a strong upper level system will bring strong to severe thunderstorms late Wednesday into early Thursday followed by cooler and drier air as Thursday progresses. The late week and weekend will remain sunny and dry but cooler than normal. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... As of 930 PM Tuesday...Breezy southwest winds have died away leaving a very pleasant evening across the eastern Carolinas. Clear skies should continue overnight with lows dipping into the upper 50s inland and lower 60s near the coast. This is virtually unchanged from the previous forecast. Where surface dewpoints are highest (along the coast) there continues to be the potential of low stratus or perhaps some patchy fog late tonight, mainly after 4-5 AM. Models show this moist layer literally only extends upward 300-500 feet before significant drying occurs aloft. This is probably too shallow for a widespread fog/low stratus event. Enjoy this calm before the storm. The discussion I`ll be writing 24 hours from now will look at a lot different! && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... As of 330 PM Tuesday...A multi-round severe weather event likely underway by Wednesday night. Early in the period the forecast is complicated by the surface low developing on the warm front as depicted by the WRF. Conversely the absence of this feature makes the warm front hard to pinpoint locally in other guidance-it appears to be well north of here. Either solution should favor fairly widespread storms early Wednesday night with the latter solutions favoring mixed severe weather mode whereas the WRF solution could favor an elevated tornado risk. Through the second half of the night all severe weather modes will be favored again, with wind and tornadoes likely eclipsing hail threat. Wind shear profiles are forecast to remain favorable and adequate for supercells and hodographs show some disconcerting maxima of SRH values of 300-400 m^2/s^2 mostly in the lowest 1 km, all in the presence of at least 1000 J/Kg of 0-6 kilometer CAPE. GFS forecasts are not quite as dramatic especially with respect to the instability but given the expected windy and warm nature of the warm sector I`d put more stock in the WRF. With the mid level forcing strong as the trough goes negatively tilted coupled with the left exit of the upper jet moving overhead we should manage to wring out any and all available instability. Thursday morning could bring one last round of storms, especially along the NC coast. The directional shear will have abated but instability maybe not so much. The final and strongest vort max rotates through keeping wind fields very strong and a linear squall line still seems possible especially in areas not overturned by the prior deep convection. These strong wind fields remain Thursday afternoon in the cool and dry advection regime and the afternoon will be quite windy especially as sunshine returns. Too early to think much about a Wind Advisory but certainly would not rule one out at this point. && .LONG TERM /FRIDAY THROUGH TUESDAY/... As of 330 AM Tuesday...The closed low over the Eastern Great Lakes early Friday will migrate across the Northeast States Fri into Sat...and will fully open up into a mid-level s/w trof as it further moves away from the lower 48 states by late in the weekend. The FA will be under cyclonic flow sfc thru aloft with 850mb temps hovering around the 0 degree C line Fri, Sat and partially into Sun. As a result, expect max/min temperatures to run up to 10 degrees F below the climatological norms for this time of the year. For the most part, it will remain dry with more clouds across the north portions of the ILM CWA then the south Fri into Sat. Isolated showers are possible across north portions of the FA due to s/w mid-level trofs or vorts rotating around the expansive closed low aloft. By Sun and into Mon, ridging aloft becomes the dominant upper feature with moderating temperatures at the sfc. Winds will stay active Fri into Sun with a progged sfc high to migrate to the FA on Mon further dropping the winds. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... As of 00Z...VFR conditions should prevail through 09Z as gusty southwest winds along the coast subside with the loss of daytime heating. The latest NAM and RAP models suggest a small area of thin stratus clouds with bases as low as 300 feet AGL could develop along the coast early Wednesday morning between 09Z-13Z. The probability of this occurring is 50-60% for the coastal airports, but only 20-30% farther inland for Florence and Lumberton. After daybreak, increasing mid-level clouds between 16-18Z will herald increasing deep moisture which should allow the development of showers and t-storms later in the afternoon. Models suggest this will be the first wave of a significant weather system that will continue well into Wednesday night. Extended outlook...MVFR/IFR conditions are likely in convection Wed night into early Thursday morning ahead of a strong cold front. Strong westerly winds Thursday could gust to 35-45 knots. && .MARINE... NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... As of 930 PM Tuesday...The strongest of the winds driven by this afternoon`s seabreeze have died away. Within the past hour wind gusts have been recorded at 17 knots at Wrightsville Beach, 21 knots in downtown Southport, and 19 knots at the buoy 5 miles southeast of Wrightsville Beach. Wind speeds should continue to gradually diminish overnight, and the Small Craft Advisory has been cancelled a little early for the South Carolina coastal waters. As seas drop below 6 feet late this evening the advisory should be allowed to expire on schedule for the NC waters. SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... As of 330 PM Tuesday...Conditions will deteriorate rapidly Wednesday night as an approaching upper trough pushes a surface cold front into the Carolinas. As this happens the wind field will strengthen dramatically through a deep layer including at the surface. Some SST/airmass stability issues that are tough to resolve this far out in time will likely dictate whether we end up with a strong SCA or a Gale Warning. Gale force gusts certainly seem likely. Frontal passage comes Thursday morning with little to no easing of the gradient so the sharp windshift will steep wave faces and further enhance the environmental treacherousness. In the cold advection regime Thursday night the deepening mixing will offset any slight decrease in gradient and we will likely remain near thresholds of Gale Warning vs Small Craft Advisory. LONG TERM /FRIDAY THROUGH SUNDAY/... As of 330 AM Tuesday...Expansive and very mature low sfc thru aloft will be centered over the Eastern Great Lakes at the start of this period. The sfc pg will remain tightened all the way down the Eastern Seaboard to Florida. As a result, W to WNW offshore winds at SCA levels will be ongoing when the long term commences. Models push a sfc trof across the local waters Fri night resulting in a slight veering of the winds to NW direction. Wind speeds will initially remain at SCA levels but do expect them to drop below SCA thresholds during Sat. As the sfc high moves closer to the area waters late Sat into Sun, winds will further drop along with significant seas. With an offshore wind thruout this period, will observe a decent range of seas due to a non-existent long period ground swell. The Cape Fear to Little River Inlet zone will have seas higher than the surrounding marine zones due to a westerly wind direction that is parallel to the coastline, for a good portion of this period. Seas will peak at the start of this period. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...Small Craft Advisory until 11 PM EDT this evening for AMZ250- 252. && $$ SYNOPSIS...MBB NEAR TERM...TRA SHORT TERM...MBB LONG TERM...DCH AVIATION...TRA MARINE...
Area Forecast Discussion
National Weather Service Lincoln IL
853 PM CDT Tue Apr 4 2017 .UPDATE... Issued at 853 PM CDT Tue Apr 4 2017 01z/8pm surface analysis shows a 998mb low over northeast Oklahoma, with a warm front extending eastward into the Ozarks. Further north, a weak bubble of high pressure is noted over southern Lake Michigan, which is keeping a dry northeasterly flow in place across central Illinois this evening. Radar is indicating a band of light precip associated with warm advection aloft: however, a distinct dry layer below 650mb as evidenced by the 00z KILX CWA is preventing measurable precip from reaching the ground. Updated the forecast earlier to include scattered sprinkles with this band. Meanwhile further west, widespread showers and thunderstorms are tracking across western and central Missouri in advance of the low. Based on radar trends and the latest HRRR data, it appears this precipitation will remain largely W/SW of the KILX CWA until after midnight. Have adjusted rain chances accordingly, to feature likely to categorical PoPs across the western half of the CWA overnight. Convection will be weakening as it pushes into the more stable airmass over Illinois, so will only mention chance of thunderstorms late tonight. && .SHORT TERM...(This evening through Wednesday) ISSUED AT 230 PM CDT Tue Apr 4 2017 Main concern this forecast period will be the track of deepening surface low and severe threat tomorrow afternoon over parts of east central through southeast Illinois. Impressive upper wave seen on satellite data over the Texas Panhandle and is forecast to track north and east with a northern stream wave eventually dropping into the Northern Plains late tonight into Wednesday which will help deepen not only the upper trof but also the surface low, which models continue to track along or just north of the I-70 corridor. Showers and elevated thunderstorms will start to push into our west later this evening and over most of the remainder of the area overnight with our far eastern and southeastern counties holding off much in the way of rain chances until closer to dawn on Wednesday. A few of the storms pushing into west central Illinois late tonight may pose a risk for some hail, but most high resolution models suggest a weakening trend as they push east of the Mississippi River late tonight. There may be a break in the thunderstorm activity over south central and southeast Illinois late tomorrow morning into the afternoon hours before the scattered cells develop in the highly sheared and unstable atmosphere to the east and south of the low track. Latest high resolution convective allowing models continue to develop discrete supercells along and just south of the surface low track and the those will race east-northeast into Indiana after 21z. Forecast soundings and instability parameters suggest the initial storm mode will feature discrete supercells with the threat for large hail, damaging wind gusts and a few tornadoes, especially along and east of the surface low and warm front, before the storms start to congeal more into a line and race east of our area by late afternoon. To the north of the low track, not a very pleasant day with frequent showers and isolated thunderstorms and an increasing east to northeast wind. As you would expect with such a dynamic storm, a large temperature gradient is expected across the area Wednesday afternoon with 70s possible over far southeast Illinois, while over our far northern counties, the mercury will struggle to get to 40 degrees. .LONG TERM...(Wednesday night through Tuesday) ISSUED AT 230 PM CDT Tue Apr 4 2017 Forecast challenge, at least with the start of this forecast period, will be the threat for some wet snow across the north Wednesday night into Thursday morning as the deep surface low tracks off to our northeast, and that will be coupled with strong northerly winds will gust up to 40 mph Wednesday night into Thursday. Forecast soundings for Wednesday night into early Thursday continue to exhibit rather warm boundary layer temperatures, plus with the fact soil temperatures are on the warm side should hold down any accumulations across the north. However, some impressive dynamic cooling expected with the deepening upper system coupled with strong lift in the dendritic zone (shown on the NAM-WRF soundings) for several hours later tomorrow evening is a concern for the potential for a few inches of wet snow across our north. For now, with the majority of the forecast soundings still too warm to support a full changeover to snow, will continue to follow the more conservative guidance which suggests less than an inch. Winds are expected to be rather brisk on Thursday as the low departs but the chill will remain as the coldest mornings look to be on Friday morning with several sites across our north dropping a few degrees below freezing so some frost headlines will probably be needed for that time frame, if not also for parts of east central Illinois early Saturday morning as the surface ridge edges slowly off to our east. For Saturday afternoon and beyond, a nice recovery in temperatures will occur with an increasing southerly flow which should result in afternoon temperatures in the mid to upper 60s Saturday, and in the 70s for Sunday and Monday as our next storm system/frontal boundary approaches increasing the chances for showers and storms again Sunday night and Monday. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 651 PM CDT Tue Apr 4 2017 VFR conditions will prevail at the central Illinois terminals through the evening before lower clouds and showers arrive after midnight. Latest radar mosaic shows widespread convection across eastern Kansas/western Missouri in advance of a deep upper low. This activity will track northeastward and weaken as it comes into the area later tonight. Based on radar trends and latest HRRR/18z NAM data, have delayed the onset of MVFR ceilings and showers until 09z at both KPIA/KSPI...with precip spreading further east to KCMI by 11z. Once this initial band of showers/thunder passes through late tonight into early Wednesday morning, it appears a lull in the steady precip will have gone with just VCTS at the TAF sites after the 15-17z time frame. Have maintained MVFR ceilings through the period until low pressure tracks along I-70 into Indiana and winds veer to the N/NE by late Wednesday afternoon and evening. At that time, IFR ceilings and showers will spill into central Illinois from the north. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Barnes SHORT TERM...Smith LONG TERM...Smith AVIATION...Barnes
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
920 PM CDT Tue Apr 4 2017 .UPDATE... 920 PM CDT For Evening Update... Only adjustment made to going forecast this evening was to slow northeastward advance of higher pops overnight per suite of high- res guidance solutions. Otherwise, only tweaks made to hourly temps based on observational trends. Evening raob data and GOES-R water vapor imagery depicts strong mid-level wrapping up across Kansas-Oklahoma. Guidance in good agreement in continuing to deepen this system as it lifts toward the forecast area through Wednesday. Strong warm air/theta-E advection developing into the lower Missouri Valley this evening will spread northeast into IL/IN by morning, with rain developing into the area in the hours after midnight. While some elevated light radar returns and spotty light rain at the surface has developed into parts of west central IL at mid-evening, increasing easterly low level flow north of the warm front across our forecast area looks to work against this precip lifting up too quickly this evening, and various high-res model guidance focuses better northeastward surge of precip after midnight. Based on this and particularly successive runs of the HRRR, have slowed the arrival of higher pops especially far north/northeast a bit from previous forecast. Still, most of the area should see rain by sunrise Wednesday morning. No changes made into Wednesday at this point, with no 00Z model data available yet. Some of the high-res, short term guidance is running a little warmer with surface temps into north central IL than some of the synoptic scale models and our forecast, though the 18Z 4km WRF does maintain colder mid-30`s readings across northwest IL/southern WI during the day. Certainly potential for strong dynamic cooling is cause for not making changes at this time. Gusty northeast winds, precipitation and chilly conditions will make for a pretty unpleasant day in any case. Updated digital grids/text products available. Ratzer && .SHORT TERM... 335 PM CDT Through Thursday... A significant and very dynamic storm system will impact the region late tonight through Thursday. This is a very complex forecast, with numerous forecast concerns, which include: 1.) Good threat for locally heavy rainfall amounts of 1-2 inches, which will likely lead to additional rises on area rivers. 2.) Potential for Rain mixing with or changing to moderate to heavy snow over far northern Illinois on Wednesday, with snow possible over Northeastern Illinois and portions of northwestern Indiana Wednesday night with accumulations possible. 3.) Strong damaging winds Wednesday night and Thursday, especially for areas along the lake shores. 4.) Coastal flooding along the lakeshore with 14+ foot waves likely By Thursday morning. Our storm system is already taking shape over the Texas panhandle early this afternoon. Model and ensemble forecast guidance continues to be in good agreement in tracking this surface low east-northeastward near KSTL by midday Wednesday, then over central portions of Indiana by Wednesday evening. This is typically a track very favorable for an accumulating snow event over northern Illinois. The main issue however, is the fact that this southern stream storm system does not have any cold air to work with. Therefore, in order for conditions to become favorable for snow, the storm system will have to dynamically produce its own cold air. Given the strength of this storm, this is certainly feasible, and I wonder if some of the global guidance is have trouble handling the cooling potential of the boundary layer Wednesday night. Its likely that as the precipitation shifts begins to develop over the area late tonight into early Wednesday morning that it will be in the form of rain. A band of strong frontogenesis is expected to develop over northern Illinois Wednesday morning, in response to the approach of the storm system. The strong ageostrophic response associated with this frontogenesis is likely to result in very strong forcing for ascent. So, while instability is rather lack luster, the presence of steep mid- level lapse rates could support some thunderstorms and a period of moderate to heavy rain during the morning. The other concern is for a change over the heavy wet snow, especially over far northern Illinois. Forecast soundings indicate that the lower level thermal profile will become marginal for snow potential. However, with the potential for mesoscale convective precipitation, the dynamical ascent could result in enough cooling to result in some wet snow during the morning on Wednesday. It appears at this time the main threat of this would be along and north of I88 in north central Illinois. If this change over to snow occurs, there could be a few hour period favorable for some heavy wet snow, with some slushy accumulations possible over far north central Illinois. A slightly better chance for a change over to snow looks to occur early Wednesday evening over northern Illinois as the mid-level system closes off over the area. The mid-level deformation band is likely to set up over northeastern Illinois and northwestern Indiana during this time, so addition bands of moderate to heavy rain/snow will be possible. Accumulation potential is very tricky given marginal surface temperatures and a warm ground. Overall, at this point it appears that up to 1 to 3 inches of wet slushy snow could occur, mainly on grassy surfaces, over portions of northern Illinois into northwestern Indiana. With this being said, the possibly for some higher amounts is not zero, especially if convective heavy snow occurs. As a result, confidence on snow amounts is low. Some lighter rain and/or snow looks to continue over eastern Illinois and northwestern Indiana into Thursday as rap around precipitation continues to feed southwestward into the area. However, it appears that much of this precipitation may become light enough to result in little chance of accumulations during the day Thursday. Expect the precip to end from west to east during the afternoon on Thursday. Overall, snow accumulation potential with this system will be tricky as surface temperatures will be marginal for accumulating snow, and ground temps will be warm. As a result, it will take some heavy snow rates to result in any accumulations of snow, mainly on grassy and elevated surfaces. Some periods of heavier precipitation is definitely possible with this dynamic system, so at least some wet snow accumulations will be possible over portions of far northern Illinois. The other concern, with this storm system continues to be the winds, particularly Wednesday night and Thursday as the surface low shifts towards New England. Strong damaging northerly winds are looking more and more likely, especially near the lake shore areas, where 60+ MPH wind gusts will blow in off of Lake Michigan. As a result of this potential, we have put out a high wind watch for the lake shore counties. Counties farther inland will also experience strong winds during this period, but magnitudes may remain in the 45 to 50 mph range. Therefore, a wind advisory will likely be needed for the inland areas as we get closer to the event. These strong winds are expected to produce 14+ foot waves, which will be crashing into the southern Lake Michigan shores Wednesday night and on Thursday. This may result in some impactful lake shore flooding and erosion. In spite of this, we have opted to hold off on upgrading to a warning at this time. KJB && .LONG TERM... 341 PM CDT Friday through Tuesday... Once the major storm system shifts out of the area, a surface ridge of high pressure will shift over the area by late Friday. This will result in lighter winds for a period late in the week. A few days of dry weather are also likely Friday through the weekend before the next storm system approaches the Upper Mid- West. Southerly winds will develop over the area this weekend allowing a much warmer airmass to shift northward over the area. Therefore, temperatures are expected to warm significantly this weekend, with 60s and possibly some low 70s possible. Shower and thunderstorm chances return to the area by Monday as another cold front approaches the area. KJB && .AVIATION... For the 00Z TAFs... Low pressure, currently centered near Oklahoma City, will lift across Missouri tonight and eventually reach central Indiana Wednesday evening. Fairly steady state conditions are expected the rest of this evening and much of the overnight hours with northeast flow and primarily VFR conditions. Stratus persists across the region early this evening between 035-045 but is expected to clear the northern terminals (RFD, DPA, ORD) by around 01Z then MDW and GYY within the next hour or so leaving mid and high clouds in place for the remainder of the evening into the overnight hours. As the low lifts into central Missouri during the predawn hours Wednesday, clouds will gradually build down with precipitation, initially virga, eventually reaching the surface around daybreak. Ceilings will drop back to IFR by mid to late morning. Rain is then expected to continue off and on, heavy at times, throughout the day. Late tomorrow evening, winds will begin to back to the north allowing colder air to filter into the region allowing a transition to a wintry mix and eventually snow. Accumulations may be possible near the very end of the 30 hr ORD TAF, but seem more likely just beyond the current TAF period. Slushy light accumulations should primarily be limited to grassy and elevated surfaces, but will have to monitor pavement temps and snow rates closely. Meanwhile, tightening pressure gradient will result in increasingly gusty winds early tomorrow morning through the afternoon, eventually peaking with gusts into the low to mid 30 kt range during the afternoon. Northeast winds much of the day will gradually back towards the north tomorrow evening. Winds just off the deck increase into the high 50kt range near the end of the 30 hr ORD TAF, and further increase to over 60KT just beyond the TAF period which could produce low level wind shear. BMD && .MARINE... 209 PM CDT A strong system will impact the Great Lakes beginning Wednesday and continuing into Friday. Expect an extended period of gale force winds with an embedded period of storm force winds. The peak winds expected late Wednesday night into Thursday. A strong low pressure system over the southern plains will strengthen as it moves to south of Lake Michigan Wednesday night into Thursday. Expect northeast gales as early as Wednesday later afternoon. The low will move into northwest Indiana late Wednesday night into Thursday, which will shift winds to northerly. This will also be the period where storm force winds are most likely. Expect a rapid buildup of waves across southern Lake Michigan, approaching 20 ft. Expect gale warnings and storm warnings to be issued. This low will strengthen further as it moves to the eastern Great Lakes, and therefore gales will likely continue through at least midday Friday. High pressure will bring some relief later Friday into early Saturday, with winds shifting back to southerly for the weekend. KMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...High Wind Watch...ILZ006-ILZ014...1 AM Thursday to 4 PM Thursday. Lakeshore Flood Watch...ILZ014...4 AM Thursday to 1 AM Friday. IN...High Wind Watch...INZ001-INZ002...1 AM Thursday to 7 PM Thursday. Lakeshore Flood Watch...INZ001-INZ002...4 AM Thursday to 1 AM Friday. LM...Gale Warning...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...3 PM Wednesday to 4 AM Thursday. Storm Warning...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777- LMZ779...4 AM Thursday to 7 PM Thursday. Gale Watch...LMZ743-LMZ744-LMZ745-LMZ777-LMZ779...7 PM Thursday to 3 PM Friday. Gale Warning...LMZ777-LMZ779...4 PM Wednesday to 4 AM Thursday. && $$ 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 Melbourne FL
939 PM EDT Tue Apr 4 2017 .UPDATE... Band of higher moisture that slipped down into our northern areas was starting to lift back to the north. This, combined with loss of daytime heating, has led to a decrease of convection across east central Florida. Some lingering light rain was occurring in the far north and will continue to diminish/lift north. A few lingering boundaries have been generating isolated showers/storms around Lake Okeechobee, but this should dissipate before midnight. Considerable mid-high level debris cloudiness should gradually lift north and allow skies to become partly cloudy in the north while the south looks mostly clear late tonight. With areas of rain wetting that occurred today, am a bit concerned about patchy dense fog, but the GFS shows southerly boundary layer flow 10-15 knots. The HRRR and local WRF show a few patches of low visibility, but not confident enough to add fog to the forecast. Temperatures will again be mild overnight with lows in the upper 60s to lower 70s. Wednesday...Strong trough digging into the deep south and the associated deepening surface low in the mid section of the country will swing a cold front through north Florida late in the day. We will be in the warm sector with southerly winds causing temps to soar into the 90s. Some record highs are possible (see below) The front should approach east central Florida late Wed night with a pre-frontal band of convection ahead of it. Atmospheric wind fields will be quite strong but the models show frontal convergence weakening and are not very bullish on POPs Wed night. A few strong storms look possible though. && .AVIATION... Mainly VFR into Wednesday. With rain wetting and diminishing clouds overnight, will have to watch for some stratus and/or patchy fog. The GFS shows boundary layer winds 10-15 knots, so would lean towards low stratus, but have not included in the TAFs yet. The atmosphere will be more stable on Wed, so we are not forecasting afternoon storms. Breezy southerly flow 15-20 knots will affect most terminals by afternoon, while a sea breeze may kick in from about KVRB-KSUA and produce gusts to around 25 knots. && .MARINE... Tonight-Wed...The pressure gradient has eased some, but on Wed the gradient will start to tighten as a cold front approaches the eastern Gulf of Mexico. The morning looks to have southerly winds 10-15 knots and then by afternoon speeds should pick up to 15- 20 knots. More gusty conditions to around 25 knots are expected along the coast, especially the Treasure coast as a sea breeze forms. && .CLIMATE... Current warm temperature records for April 4th and 5th: LOC DATE HI-MAX HI-MIN DAB 4-Apr 93 1974 70 1991 MCO 4-Apr 93 1918 69 1974 MLB 4-Apr 92 1977 71 1974 VRB 4-Apr 92 2012 73 1960 DAB 5-Apr 90 1957 70 1954 MCO 5-Apr 91 1999 68 1957 MLB 5-Apr 91 1977 72 1957 VRB 5-Apr 90 1977 73 1957 && .PRELIMINARY POINT TEMPS/POPS... DAB 69 90 68 79 / 20 10 50 30 MCO 69 92 69 79 / 20 10 40 30 MLB 71 90 71 83 / 10 10 30 30 VRB 71 89 70 84 / 10 10 30 30 LEE 70 92 68 77 / 20 10 50 30 SFB 70 93 68 79 / 20 10 40 30 ORL 71 92 70 79 / 20 10 40 30 FPR 70 89 69 85 / 10 10 20 30 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && $$ Forecasts...Lascody Impact Wx...Blottman
Area Forecast Discussion
National Weather Service Marquette MI
740 PM EDT Tue Apr 4 2017 .SHORT TERM...(This evening through Wednesday) Issued at 357 PM EDT TUE APR 4 2017 Water vapor imagery and RAP analysis show a continued active southern stream with one batch of shortwave energy lifting ene across the Lower Great Lakes region and a second vigorous wave moving out of the southern Rockies. To the n, a mid-level low was over southern Hudson Bay. At the sfc, low pres associated with Great Lakes shortwave was over southern Ontario while upstream wave was suporting low pres over the southern Plains. Another low was over southern Hudson Bay. Northerly gradient wind btwn the low over southern Ontario and high pres over Manitoba was bringing drier air into Upper MI. In fact, in the last hr or so, sfc dwpts have fallen well down into the 20s over portions of western Upper MI. As a result, low clouds and some fog that dominated early in the day have cleared out steadily from nw to se, leaving behind thinning high clouds. Under a brisk northerly wind, temps currently range from around 40F near Lake Superior to well into the 50s s central. Expect a quiet night tonight with fcst soundings showing dry low to mid levels beneath lingering high level moisture/ci cloudiness. Diminishing gradient wind will allow for a cool night with some high cloudiness preventing a colder night. Favored the lower side of avbl guidance for mins. Normal cold areas will fall to the low/mid 20s. Expect mostly 30s at lakeside locations along the Great Lakes. On Wed, the next southern stream low pres system lifting ne to central IL/IN by evening will be too far s to bring any pcpn into Upper MI. However, it is noted that a few models, GFS and CMC in particular, do develop some -shra over parts of central Upper MI Wed aftn along a weak sfc trof that pushes se into the area. This trof is associated with the tail end of a shortwave swinging thru northern Ontario. There has been quite a bit cu/stratocu development upstream from nw MN into northern Ontario this aftn, but no indications of pcpn yet per Environment Canada radars. There are sct shra/tsra farther w in eastern ND where a little more instability is present along with assistance from shortwave over western ND. Not out of the question that a -shra or two/some sprinkles could develop Wed aftn, but with more limited moisture/instability over Upper MI on Wed, a mention in fcst is not warranted attm. Increasing clouds and developing e to ne winds will limit warming. Expect highs mostly in the 40s, though a few spots will probably top 50F in the interior. .LONG TERM...(Wednesday night through Tuesday) Issued at 324 PM EDT TUE APR 4 2017 Nam has a trough in the central U.S. 00z Thu with a ridge over the Rockies and a trough off the west coast. This trough moves into the ern U.S. 00z Fri with the ridge moving into the Rockies. The ridge moves through the plains on Fri. System stays to the south and east of the area Wed night into Thu with slight chance pops only for the far east. There will also be slight chance for upslope pcpn for Thu morning and there could be some mixed pcpn of freezing rain, rain and snow with this. Will then be dry through fri. In the extended, GFS and ECMWF show a 500 mb ridge over the plains into the upper Great Lakes 12z Sat with troughing on both coasts. The ridge builds into the Great Lakes region with troughing in the western U.S. 12z Sun. The trough moves into the plains 12z Mon and then into the upper Great Lakes 12z Tue with colder air coming back into the area on Tue. Temperatures will be above normal this forecast period until Tue when the colder air comes in and drops temperatures to near normal. Dry weather continues into Sun morning before a slow moving cold front approaches the area and brings in a chance of rain. There could be some snow mixed in for Tue morning across the far west and north. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 728 PM EDT TUE APR 4 2017 Lingering gusty winds at SAW wl diminish quickly this evng as a hi pres rdg blds over Upr MI and daytime heating/mixing ends. Then expect VFR conditions and light winds to prevail this fcst period with the dry hi pres dominating. There wl be some diurnal cu dvlpg on Wed with daytime heating especially at SAW, but cigs wl remain above 4k ft. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 357 PM EDT TUE APR 4 2017 Initially this evening, nw winds may be as high as 20-25kt over eastern Lake Superior. Otherwise, diminishing pres gradient will allow winds to diminish to under 15kt across Lake Superior tonight. Winds will be under 20kt on Wed. As low pres tracks ne to the Lower Lakes/Upper Ohio Valley Wed night/Thu, n to ne winds will increase to 20-30kt. Could be some gale force gusts over the eastern part of the lake. Winds will diminish from w to e Thu night/Fri with winds blo 20kt across the lake by Fri evening as a high pres ridge arrives. With the departure of the ridge on Sat, southerly winds will increase, more notably over the eastern part of the lake as is typically the case for southerly winds. Expect winds of 15-25kt across the eastern Lake. Winds should diminish some for a time on Sun as a low pres trof settles over the area. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...07 AVIATION...KC MARINE...Rolfson
Area Forecast Discussion
National Weather Service Mount Holly NJ
944 PM EDT Tue Apr 4 2017 .SYNOPSIS... A cold front will move offshore later this evening, then weak high pressure follows for Wednesday. Intensifying low pressure in the Ohio Valley Wednesday night becomes quite strong as it tracks across Pennsylvania on Thursday. It then drifts northeastward over New England Friday and Saturday. High pressure eventually builds in from the west by Sunday and becomes nearly stationary off the Mid Atlantic coast early next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... Low pressure that developed along a triple point continues to move northeast of our region. The leftovers of a warm front while initially near our northern zones, has slipped back southwestward. This appears to have been enhanced by several showers during the afternoon across the northern part of New Jersey, and added to the cooler boundary layer there. This colder and more dense airmass was then pushed southwestward as significant warmth was occurring on the other side of the boundary. This boundary seems to have mostly dissipated as it moved farther southeastward, however there is an area of low clouds across northern and central New Jersey. This has even expanded south and west some early this evening. Some guidance which shows this tends to not expand it much more. We therefore increased the cloud cover quite a bit into the overnight hours over these areas, and added fog for a time closer to the coast although we are not anticipating widespread dense fog. A cold front entering our western zones will clear the coast later this evening with some drying. The dew points have already dropped across the western areas. However, the damage may have been done with the low-level moisture stuck in place for awhile where it currently is. This update is of lower confidence given the low clouds, however hopefully this latest update tipped the forecast in the right direction. Some lingering showers up across the northern areas are expected to dissipate by Midnight. As a result, the PoPs were adjusted once again to reflect this along with radar trends. The temperature, dew point and wind grids were adjusted based on observational trends along with some helpful guidance from the HRRR model. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... A nice day is expected Wednesday, the calm before the storm per say. Weak high pressure affects the area during the first half of the day, before shifting offshore. There may be a period of at least some stratocumulus development during the first part of the day as convective temperatures are reached and before the moist layer near the inversion can mix out. Some forecast soundings indicate this and therefore the cloud cover may need to be increased for a time. Thereafter, some cirrus should arrive. No precipitation is forecast through the daytime hours. Northwesterly winds strongest in the morning hours then should lessen and turn west and southwest in the afternoon, before becoming light southeasterly as we approach early evening. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... **Stormy Thursday with attendant hazards** 500 mb: A strengthening closed low in the Ohio Valley Wednesday night marches northeastward across PA on Thursday and into NYS Thursday night, before weakening over and east of New England this weekend. Very strong ridging follows early next week with potential for near record warmth! Temperatures: Calendar day averages 5 to 10 degrees above normal Thursday (5 north 10 south), near normal Friday-Sunday, then warming rapidly early next week with calendar day averages about 15 degrees above normal next Tuesday. Forecast basis: a 50 50 blend of the 12z/4 GFS/NAM guidance Wed night- Thu night, unless otrw noted, then the 12z/4 MEX MOS for Fri, and thereafter, the 15z WPC guidance Fri night-Tue. Wednesday night into Thursday... Note the forecast for Thurs"day" from the vicinity of RDG-ABE- SMQ northward was mostly the colder NAM temps! Flood potential: Flood watch issued. Please see the hydro section for more information. Widespread rain develops during late Wednesday night and becomes heavy at times for 3 to 6 hours ahead of the 985-988MB triple point low that develops east of the parent W PA 985MB low. That triple point low is currently mesoscale modeled newd just west of I-95 during the day Thursday. That pattern favors se flow e of I-95 with a reduction in potential rainfall there (NJ coast) but enhancement along and west of the path of the sfc low where 1-2" of rain should fall in 6-12 hours. That will result in spotty small stream flash flooding depending on the axis of heaviest rain...hopefully northwest of the I-95 highly urbanized corridor. Wind: 15 mb 6 hr pres falls should induce a period of strong se winds that shift southwest late in the day with the passage of the cold front. Suspect a smattering of se gusts 40 to 50 mph in the se inflow axis and then an hr of sw wind caa 40 to 50 mph gusts south to north 19z-23z in the brief shot of strong caa and asstd pressure rises. We may need a short fuse wind advisory for NJ/DE I95 eastward to the coasts Thursday for sct gusts around 45 mph. Coastal Flooding: Ekman transport favors pulling water away to the right, into the Atlantic on southerly flow but in this case....sfc pressure down to 990 mb on the coast and a period of 35-45 MPH ese gusts ahead of 7mb 3 hr pres falls, should build positive departures near 2 feet more in line with SIT NYHOPS for Sandy Hook region (likely minor threshold, tiny chc mdt), and certainly much greater than the ETSS and ESTOFS. Confidence is above average that the SIT will be more accurate to use, especially considering ETSS performance this morning with near minor threshold inundation flooding in NJ. SVR: Pls follow SWO DY3,2,1 as the days pass, as well as our office discussions. It appears to me that we will be seeing strong or svr tstms racing newd from Va during the early morning hours and weakening as they move north of the Delmarva during midday. Strong wind fields and bulk shear both 0-3 and 0-6km, subzero LI, TT 50-55 suggest the potential is significant for the Delmarva prior to Noon Thursday. Very little effort was put into this latter portion of the forecast and have relied heavily on WPC. Thursday night through Friday...some bands of precip may linger, especially in the higher terrain of the Poconos and NW NJ given cyclonic flow, cooling aloft asstd with the strong 500 mb trough passing overhead Friday. Snow may mix in with the rain at higher elevations Friday or Friday evening, though at this point accumulating snow appears very unlikely. Gusty west winds develop later Friday. Saturday...drier with sunshine and a gusty northwest wind to 25 mph. Sunday through Monday...With the high building in, tranquil weather should return. This could set the stage for efficient radiational cooling conditions on Sunday night leading to possibly a frost advisory across northern Delmarva (frost/freeze program has yet to begin for NJ or southeastern PA. At this point however, it is highly unlikely temps will drop to 35F or less for anything more than an hour. A major warmup develops Monday that could build to near record warmth Tuesday The records for the 11th are 84 at ACY and PHL (1887) ILG-1922 and ABE-84 2011. GED is 83 in 2013. RDG 85-2011, TTN 86-2011, MPO 77-1955. I did raise temps next Tuesday with 13C overhead at 850mb, southwest flow and a probable 2m temp at PHL near 75F. It may be that cooling sea breezes keep temps a few degrees cooler than fcst in far southern NJ. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Tonight...VFR overall. However MVFR/IFR ceilings (MVFR visibility) should impact TTN and may get close to ABE, PNE and ACY for awhile as a marine layer occurs ahead of a cold front. There is low confidence in how far south and west the low ceilings get for awhile tonight. A few lingering showers this evening mainly north of ABE to TTN. The winds should mostly be westerly 10 knots or less, or even locally light and variable. Wednesday...VFR with some cloud bases between 3500-5000 feet. Northwest winds around 10 knots in the morning, then winds become west to southwest in the afternoon before turning light southeast approaching early evening. Outlook... Wednesday night into Thursday...Conditions (both ceiling and visibility) will deteriorate to intermittent IFR as showery rains arrive late Wednesday night and continue through at least mid day Thursday. There is a good chance for thunderstorms. Additionally, there is a risk of low level wind shear Wednesday night through mid day Thursday as there will be a sharp directional shear through this time from southeasterly at the surface to southerly or southwesterly in the low to mid levels. Winds at 10000 to 1500 ft are likely to be 50-55 kt for a 2 to 4 hr period Thursday morning. Thursday night through Friday...Bands of showery rains may rotate eastward across the forecast area but in general, conditions should gradually improve to VFR CIGS through this time. West or northwest winds may gust 30 kt Friday evening asstd with pres rises and trough passage. Saturday and Sunday...VFR. Northwest winds gust 25 kt Saturday and 15 kt Sunday., && .MARINE... Some fog looks to persist in the Atlantic coastal waters mainly for the two northern zones. It appears dense fog should not be widespread or long in duration, therefore no advisory at this time. The Small Craft Advisory continues across the Atlantic coastal waters mainly for elevated seas. Seas should be 4-7 feet but slowly subsiding through the night and Wednesday. OUTLOOK... Gale watch issued most of the waters...marginal both in duration and above threshold. Wednesday night and Thursday...E-SE winds increase Wednesday night then veer out of the S Thursday behind a warm front. A strong SCA will occur with wind speeds forecast to increase to 20-25 kt. Model soundings show a very strong wind field aloft w/ 50 kt winds only a few hundred feet off the ground. Normally this not a set up for downward transfer of stronger wind but nearshore...with the pressure being so low and 15 mb 6 hour pressure falls....odds increase for sely gale force wind transfer of 35-40 kt for 2-4 hrs ahead of the cool front and 1 hr of gale force sw wind gusts behind it as pressures start rising rapidly. Special marine warnings may also be needed where bands of showers and embedded thunderstorms imply concentrations of surface wind momentum transfer, especially Thursday morning into early afternoon. Friday and Saturday...winds will slowly diminish, but should generally remain near or just above 25 kt for much of this period. headlines anticipated. && .HYDROLOGY... Flood potential: Flood watch issued. Widespread rain develops during the night and becomes heavy at times for 3 to 6 hours ahead of the 985-988MB triple point low that develops east of the parent W PA 985MB low. That triple point low is currently mesoscale modeled newd just west of I-95 during the day Thursday. That pattern favors se flow e of I-95 with a reduction in potential rainfall there but enhancement along and west of the path of the sfc low where 1-2" of rain should fall in 6-12 hours. That will result in spotty small stream flash flooding depending on the axis of heaviest rain...hopefully northwest of the I-95 highly urbanized corridor. 1. MMEFS etc. Two to three inches of rain, from about Philly north, were inserted into the hydro models this morning over the next 72 hours. River forecasts assume that this rainfall will occur. If is doesn`t, crests will be lower. 2. The Passaic River is running high. Pine Brook will remain above Action Stage until the next surge of rain on Thursday. It appears the gauge will crest just under flood stage early on Wednesday. Water levels will begin climbing once again late Thursday into Friday. All of our Passaic River forecast points will see rises. 3. Across the Raritan basin, forecasts points have dropped below Action Stage. More flooding is possible beginning Thursday. Flooding could persist into the weekend on the Raritan and Millstone. 4. With the 12z models showing a slight lowering in the qpf amounts, especially across our southern zones, we only issued the Flood Watch from about the I95/I78 intersection northeastward, considered most vulnerable at this point in time. The watch runs from 12z Thu through 18z Fri. If future precipitation totals increase across our southern zones, the Flood Watch could be expanded southwestward to include PHL/ILG and points northwest to the Poconos. So if you live along the Rancocas, the Schuylkill, or along the quicker responding streams across SE PA and NRN DE, remain informed. 5. The potential for flooding can be broken down into three different types. Low lying and poor drainage flooding would occur first during the day Thursday soon after the rain begins. The runoff will drain and potentially produce flooding later Thursday into Thursday night along smaller creeks and streams. Lastly, some larger rivers and mainstems will rise and could flood Thursday night into Friday. The river flooding could easily last into or through the weekend, depending on the magnitude of the rainfall Thursday. 6. Please refer to AHPS for the latest. Confidence is higher that a number of forecast points will hit their Flood Stage. But with rainfall still 36-48 hours in the future, confidence is much less regarding any moderate flooding that is modeled. 7. The potential for flooding increased during the last week because of three successive rain events. With each event, waters are starting to rise from a higher point/level. The rivers have not had a chance to return to their base flow. && .TIDES/COASTAL FLOODING... In case you noticed... the Tidal DE near Philly came within an inch minor flood this morning around 830 am. Guidance was less than what occurred. Ekman transport favors pulling water away to the right, into the Atlantic on southerly flow but in this case....sfc pressure down to 990 mb on the coast and a period of 35-45 ese gusts ahead of 7mb 3 hr pres falls, building positive departures more in line with SIT NYHOPS for Sandy Hook region (likely minor threshold, tiny chc mdt), and certainly much greater than the ETSS and ESTOFS. Confidence is above average that the SIT will be more accurate to use, especially considering ETSS performance this morning with near minor threshold inundation flooding in Elsewhere...The upper MD Eastern Shore has a smaller chance of a minor tidal indunation flood episode Thursday afternoon in the southerly flow, though there, the risk appears to be less than near Sandy Hook NJ. Finally: its not impossible to see approaching minor flood threshold for the Thursday evening high tide vcnty PHL. All this will be reviewed again tomorrow, especially with regard to timing the inflow wind shift abatement. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...Flood Watch from Thursday morning through Friday afternoon for NJZ001-007>010-012-013-015. DE...None. MD...None. MARINE...Gale Watch from Thursday morning through Thursday afternoon for ANZ431-450>454. Small Craft Advisory until 6 AM EDT Wednesday for ANZ450>455. && $$ Synopsis...Drag Near Term...Gorse Short Term...Gorse/Robertson Long Term...Drag Aviation...Drag/Gorse Marine...Drag/Gorse/Robertson Hydrology... Tides/Coastal Flooding...
Area Forecast Discussion
National Weather Service Pueblo CO
813 PM MDT Tue Apr 4 2017 .UPDATE... Issued at 810 PM MDT Tue Apr 4 2017 Radar trends and HRRR guidance indicates a chance of some accum snow, especially across the Pikes Peak region (especially N facing slopes) and along the US50 corridor from ~Salida to ~Canon City. Have upped pops and QPF these regions. Accums should be ~1-4" This precip is associated with a well advertised 2nd disturbance coming down the backside of the trough that moved across us earlier today. /Hodanish && .SHORT TERM...(This evening through Wednesday) Issued at 352 PM MDT Tue Apr 4 2017 Satellite images this afternoon are showing the upper level low over the OK panhandle. Radar shows some convective snow showers wrapping around the low into southeast CO. Although pcpn is not as widespread as it was this morning, under the heavier showers there could be a quick inch or two of snow accumulation. Temps have been warming a little as pcpn has ended or lightened and some locations have switch from snow to rain. Tonight the upper level low will continue its eastward track away from southern CO, however a weather disturbance to our north will be moving south through CO and is expected to bring another round of snow, mainly to the central CO mtns, Pikes Peak, Teller county, the Sangre de Cristo and Wet mtns, and the I-25 corridor. For this reason, I am reluctant to take down the winter weather highlights that are in effect thru 06Z, even though some of these areas are currently seeing a lull in the snow activity. Will downgrade remaining Warnings to Advisories and will remove the highlights for the southwest mtns. The best chances for snow with the approaching disturbance are expected from late this evening through late tonight, with pcpn ending from north to south along the eastern mtns and I-25 corridor. El Paso and Teller counties may see the best chances for snow end around 2-3am, while the Trinidad area could see snow until around 5 or 6 am. Some areas of fog may develop late tonight as well. Wed will be a dry day as an upper ridge starts to build over the area. Temps are expected to warm into the 40s and 50s at the lower elevations. .LONG TERM...(Wednesday night through Tuesday) Issued at 352 PM MDT Tue Apr 4 2017 Overall, more subdued meteorological conditions are anticipated over the majority of the forecast district during the longer term, especially when compared to the previous 10 days or so. Primary longer term meteorological issues during the longer term include generally above seasonal temperatures, gusty winds at times as well as basically low grade pops at times(including the potential for isolated thunderstorms). Recent longer term PV analysis, computer simulations and forecast model soundings indicate that an upper ridging pattern will develop over southern Colorado from Wednesday night into Saturday morning allowing for generally dry conditions in combination with warmer temperatures during this time-frame. Then, next upper disturbance is expected to impact the forecast district from later Saturday into Sunday evening allowing for increased pops, including the potential for isolated primarily afternoon thunderstorms(favoring higher terrain locations) both Saturday and Sunday. Then another round of unsettled conditions(including thunderstorms favoring far eastern portions of the forecast district) will be possible from later Tuesday into next Tuesday night with next system. Regarding winds, at this time, it appears that the highest potential for gusty winds should be noted from later Friday into Sunday night. Finally, during the longer term, generally near to above seasonal early April temperatures are anticipated during the majority of the longer term with the warmest temperatures expected from Friday into Saturday. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 352 PM MDT Tue Apr 4 2017 Showers will be possible in the vicinity of KCOS and KPUB through late tonight. At times VFR conditions can be expected, but periods of MVFR conditions will continue at least into the late night hours. A new weather disturbance moving south through the area later tonight, could bring a period of heavier snow to KCOS and KPUB, which could result in IFR ceilings and visibility, there may also be some fog in the early morning hours on Wed. VFR conditions are then expected by about midmorning. KALS could continue to see some showers in the vicinity into this evening, which could bring lower CIGS and VSBY at times. Late tonight some fog may develop in the area, reducing the VSBY and there could be a low ceiling, otherwise VFR conditions can be expected Wed. && .PUB WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until midnight MDT tonight for COZ058>063-072>076-078>082-084-087-088-094. && $$ UPDATE...HODANISH
Area Forecast Discussion
National Weather Service Topeka KS
913 PM CDT Tue Apr 4 2017 .UPDATE... Issued at 909 PM CDT Tue Apr 4 2017 Have made adjustments to the POP/QPF forecast through 06Z to better reflect the effects of the dry slot punching into the southern CWA and the erosion of the northern periphary of the def zone as dry air intrudes from the north. How quickly the def zone pivots around will affect rainfall totals across the SE CWA, which will also have a direct effect on river response in the coming hours/days. && .SHORT TERM...(This evening through Wednesday) Issued at 315 PM CDT Tue Apr 4 2017 Mid/upper level low pressure currently located over the Texas panhandle and northern New Mexico. Ahead of this low pressure is a band of frontogenesis that stretches northeastward through eastern KS. A band of rain has developed is in response to this forcing. Current radar shows convective elements and the latest RAP soundings have shallow elevated instability. This band is forecasted to gradually lift northward through the afternoon. As the main system progress eastward a surface low pressure will track through extreme southeast KS. Widespread convection is expected to develop in the vicinity of the warm front. It is during this time that mid level lapse rates steepen which will result in 100-300 j/kg. This elevated instability will move over east central KS during the late evening and early morning hours. Perhaps one of the stronger cells could be capable of producing large hail mainly along and south of I-35. It is during this time frame that persistent convergence north of the warm front and upper level support could lead to cell training as well. The other expansive area of rainfall will develop in the trowal of the mid level low pressure in central KS, which will track through eastern KS through tomorrow morning. A widespread 1-2 inches of rainfall is possible by noon tomorrow. There are several models suggesting that rainfall totals could exceed 3 inches in some areas. In fact the ARW ensembles have a 100 percent chance of 2 inches of total rainfall within 25 miles of a point. In the same exact area the nested NAM has an area of greater than 3 inches of total rainfall. The best chances for these higher amounts will be where the elevated convection and trowal precipitation overlap. As of now the strongest signal for this is along and near the KS turnpike. Unfortunately all of this region has seen above normal rainfall therefore the soil is already saturated. Given these conditions and the going forecast flash flooding could not be completely ruled out. River flooding is more likely after the event wraps up so a flood watch has been issued. As the system passes through the low pressure gradient will cause surface winds to become gusty overnight. Temperatures tonight drop into the 40s so the combination will cause winds chills just above freezing. This along with rainfall will make for some miserable conditons. Tomorrow morning the low pressure systems lifts northeastward causing the rain to end from west to east. Most of the rain should come to an end in the late morning hours. .LONG TERM...(Wednesday night through Tuesday) Issued at 315 PM CDT Tue Apr 4 2017 Wednesday Night through Tuesday... The start of the extended period will consist of decreasing clouds and cool temperatures. A surface and upper-level low will continue progressing away from the outlook area. In doing so, winds will begin to lighten and skies will begin to clear. Morning lows are expected to dip into the mid and upper 30s Thursday morning and low to mid 30s Friday morning. RH values are expected to approach the 80- 90 percent range both mornings, therefore have a mention for patchy to areas of frost. Upper-level ridging will then dominate for the reminder of the week into the first half of the weekend. Southerly flow will return by Saturday as a surface high progresses into the southeastern US. In response, temperatures will surge into the low to mid 70s. We then turn our attention to the potential for thunderstorms Sunday afternoon and evening. Starting in the upper levels, guidance suggests an open H500 wave with an embedded shortwave across the central US. At the surface a trough will progress across the forecast area during the afternoon and evening hours. Forecast parameters continue to hint at the possibility for a few strong to perhaps severe thunderstorms. Zonal flow will then dominate the remainder of the period with high temperatures in the 60s. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 649 PM CDT Tue Apr 4 2017 Widespread showers will persist throughout the evening and overnight hours with current VFR/MVFR cigs/visbys falling to low MVFR/IFR levels. Scattered thunderstorms will be possible across east central Kansas through this evening with the threat for thunderstorms waning by midnight. N/NW winds will increase through the night behind the departing low with sustained winds of 20-25 kts and gusts of 30-35+ kts expected for the morning. This winds will persist through much of the day but gradually subside by the afternoon. && .TOP WATCHES/WARNINGS/ADVISORIES... Flood Watch through Wednesday afternoon for KSZ010>012-021>024- 026-035>040-054>056-058-059. && $$ UPDATE...Skow SHORT TERM...Sanders LONG TERM...Baerg AVIATION...Skow