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

Area Forecast Discussion...Updated
National Weather Service Billings MT
904 PM MDT Mon Apr 3 2017 .UPDATE... Broad amorphous upper level low continues a slow progression southward along the MT Continental Divide this evening. There area several meso-circulations within the synoptic system each producing areas of precipitation. Will continue to see scattered areas of mainly light snow overnight as this system slowly slides south and opens up into tomorrow as a kicker wave arrives. Red Lodge webcams showed a period of snow result in maybe half an inch around 8pm, however confidence in moderate snowfall for the Beartooth front tonight is dropping as winds haven`t turned to a favorable direction for heavier snowfall so far this evening. Hi- Res models keep winds just a bit northwest through the night and just bring a few bands of snow through for the rest of the night there. However if winds turn just a bit more northerly (20 degrees might do it) there is sufficient lift and instability for a quick accumulation of several inches in these areas. In addition, Metro model runs showing road temperatures dropping to freezing by 1030pm, so even lighter snow may bring some enhanced travel difficulties by morning in these areas. Given the above, tweaked snow accumulations down just a bit but will hold on to the advisory for now based mainly on travel icy road potential. Will also keep an eye on some light snow accumulation potential along and south of US212 across southeast MT overnight into tomorrow morning as HRRR and RAP showing a bit more qpf in those areas lined up with some upper divergence. Chambers && .SHORT TERM...valid for Tue and Wed... Latest 500mb analysis shows a weak low over western MT and a stronger circulation in northeast MT near Malta. To our east, instability axis resides on the Dakotas side of our eastern border, with scattered showers and a few recent lightning strikes just outside of our cwa. Western low and its cold pool aloft is resulting in increasing shower coverage across our west/central parts...but no lightning noted yet. Showers over our west will continue to increase over the coming hours with diurnal destabilization and as western trof drops southward allowing for winds to veer more northerly. P-type will be a combination of rain/snow/graupel with very low freezing levels in place and surface wet bulb temps that are in the low- mid 30s. The veered mid level winds will favor the north slopes of the Beartooth/Absarokas and have already issued a winter wx advisory for a few inches of snow for Red Lodge/Mcleod. Given the steep lapse rates and dendritic layer below mtn top, snowfall rates may reach or exceed an inch per hour for a short time. Moisture will shallow out over time, and snow showers should become lighter or diminish overnight. Trowal associated with NE MT low will wrap some light rain/snow into our central and eastern parts late tonight and Tuesday. Some increased NW wind will accompany the pcpn, along with cool temps, so a somewhat raw day in store for our eastern CWA tomorrow. The Bighorns should pick up a few inches of snow per the NW flow. For Billings, best chance of rain/snow showers appears to be early this evening with wind shift, then late tonight into early Tuesday with trowal from the north...the latter of which may be trumped by downsloping NW winds. Best chance of pcpn tomorrow will be east of Billings. Ridging/anticyclonic flow will spread in from the west Tuesday afternoon and evening, marking the beginning of a period of dry weather. Dry conditions will prevail Wednesday and Wednesday night. Temps will remain seasonably cool tomorrow with highs in the 40s to lower 50s. Highs will return to the 50s/lower 60s Wednesday per the ridge and downslope winds. JKL .LONG TERM...valid for Thu...Fri...Sat...Sun...Mon... Dry weather in the first part of the extended period will give way to unsettled conditions in the latter portion of the period. A high amplitude ridge should dominate our weather on Thursday. The ridge axis will shift into the Dakotas Thu. night, allowing SW flow to overtake the region. It will be dry and warm under the ridge with temperatures around 70F on Thursday due to 850 mb temperatures of +14 to +16 degrees C. Some shortwave energy and diffluence moves over the region on Friday bringing some low PoPs to the western high elevations. 850 mb temperatures will reach +18 degrees C, so highs will be in the 70s from Billings and east. For the weekend and early next week, the large-scale upper flow pattern turns cyclonic with several shortwave troughs or potentially upper lows moving over the region. This pattern favors rain showers across the lower elevations and snow showers in the mountains. Models agree on the large-scale cyclonic flow pattern but differ on the smaller-scale features. There will be periods of dry weather as well...but timing these periods is difficult this far out. High temperatures should generally trend cooler, from the 60s on Saturday to the 50s on Sunday and Monday. RMS/JKL && .AVIATION... VFR will prevail tonight. Scattered showers and isolated thunderstorms will affect the region this afternoon and evening with associated MVFR/IFR conditions. Rain and snow showers with areas of fog will continue over the area tonight with MVFR/IFR conditions. There will be areas of mountain obscuration through tonight. RMS/JKL && .PRELIMINARY POINT TEMP/POPS... Tue Wed Thu Fri Sat Sun Mon ----------------------------------------------------------- BIL 031/049 030/061 041/070 047/072 047/062 041/055 036/051 55/O 00/B 00/B 01/B 23/W 23/W 33/W LVM 024/047 027/059 037/067 040/066 041/058 034/052 030/051 44/S 00/N 00/B 02/W 33/W 33/W 23/W HDN 031/050 027/060 035/072 041/073 044/064 039/056 034/052 55/O 00/U 00/B 01/B 23/W 33/W 33/W MLS 033/049 030/060 037/071 044/076 047/067 041/056 035/051 35/O 10/U 00/B 01/B 13/W 33/W 33/W 4BQ 029/047 026/057 034/070 043/075 046/066 040/056 034/051 24/O 00/U 00/B 00/B 13/W 23/W 33/W BHK 030/047 026/055 031/067 040/075 045/067 039/055 032/049 25/O 20/U 00/B 00/B 13/W 33/W 23/W SHR 028/044 024/057 032/066 038/069 041/061 037/054 032/050 44/O 00/U 00/B 01/B 13/W 23/W 33/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...Winter Weather Advisory in effect until 6 AM MDT Tuesday FOR ZONES 56-66. WY...None. && $$
Area Forecast Discussion
National Weather Service Columbia SC
841 PM EDT Mon Apr 3 2017 .SYNOPSIS... Dry and warm weather is expected Tuesday before yet another strong system impacts the area Wednesday with another round of severe weather possible. Cooler and dry Thursday into the weekend as high pressure settles over the region but windy conditions expected Thursday. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... Update 745 pm - Round One of a busy severe weather week moved out of The Midlands before 7 pm. We are collecting reports of probable tornado damage as well as downed trees. Two teams will be out tomorrow to survey the worst damage. Scattered showers will be possible overnight mainly south of I-20 as a band over southeast Georgia may skirt the region. Update 505 PM - A line of strong to severe thunderstorms was along a north to south line from east of Charlotte through Columbia to Orangeburg as of 5 pm. We have received reports of possible tornado touchdowns, numerous trees down, and localized flash flooding. This line will continue to push east across The Midlands and Pee Dee Region and should clear our service area by 7 pm. Moisture and instability continue increasing across the forecast area with showers and thunderstorms becoming more numerous. Main concern through tonight remains the front currently moving through eastern GA and the potential for severe weather. With very strong winds aloft and plenty of instability have coordinated with SPC in the issuance of tornado watch 119 through 9 pm. Expect the main threat of severe weather to begin arriving in the CSRA between 3 and 4 pm and the Midlands between 4 and 5 pm. Along with the potential for tornadoes the freezing level and wet bulb zero heights support potential for hail. Although the cells will be progressing rapidly to the northeast there is the potential for locally heavy rainfall with rainfall rates up to 2 inches per hour. Main line of convection will move east of the forecast area by 9 pm with a few showers and thunderstorms lingering overnight. Winds will also remain strong and gusty as the system crosses the area so the lake wind advisory will remain in effect through 4 am. With cloud cover and winds persisting overnight expect low temperatures in the lower 60s. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... For Tuesday and Tuesday Night: A return to dry weather expected behind the front. Do not anticipate much in the way of cooler temperatures behind the weak front. With more sunshine expected, afternoon temperatures should climb back into the 80s. The dry weather will continue for the majority of the overnight hours Tuesday night. Moisture will begin increasing once again late in the night across the western counties in advance of the next approaching weather system, but any rainfall will hold off until sunrise or later on Wednesday. Lows Tuesday night will remain mild in the 50s to around 60 degrees. Wednesday and Wednesday night: Active weather returns. More severe weather will be possible. Another strong upper trough will be moving towards the region, with southwesterly flow aloft in advance of the trough. A surface warm front will once again be lifting northward through the cwa during the morning, while the main cold front will still be well west of the area. In advance of this cold front, a warm, moist, and unstable airmass is expected to be setting up across the cwa through the day. Aloft, a strong 850 mb jet will be moving through the area, with 55-60+ knots. The combination of a 500 mb flow that will be diffluent over the region, and a strong jet max at 250 mb, will both help to enhance lift over the region by the afternoon. Strong thunderstorms are expected to develop in a moderately unstable airmass by the afternoon hours. With the strong low- level jet, a damaging wind threat will be possible with the storms. With the expected instability, the threat for hail and an isolated tornado will also remain. There could be a couple of rounds of strong storms as well, the first during the afternoon in the vicinity of the retreating warm front, then the second round late Wednesday afternoon and into Wednesday night ahead of the approaching cold front. High temperatures Wednesday around 80 to the lower 80s, and lows Wednesday night in the middle 50s. && .LONG TERM /THURSDAY THROUGH MONDAY/... The front will be exiting the region by Thursday morning, and very windy conditions are forecast to develop behind the front. Sustained winds around 20 mph, with wind gusts over 30 in many areas, appear to be possible during the day. A Lake Wind Advisory will likely be required during the daytime hours on Thursday, with the possibility of another one on Friday. As high pressure builds in behind the front, a return to dry weather is expected through the entire long term period. Winds will be out of a northwesterly downslope direction for much of the period. There will be a noticeable cool down in regards to temperatures behind this front associated with the high pressure. Temperature readings will be at or below normal Thursday through Saturday. By Sunday temperatures return back to normal, with Monday above normal. && .AVIATION /01Z TUESDAY THROUGH SATURDAY/... Strong convection has shifted east of the terminals. There will be lingering low-level moisture. Observation trends and the HRRR suggested IFR ceilings moving into the area from the northwest tonight. These ceilings were also supported by the GFS LAMP. Boundary layer wind should limit fog. The KCAE 88D VAD Wind Profile supported the NAM with a strong low-level jet. Expect either gusty winds or low-level wind shear continuing tonight. Believe there will be enough of an inversion to lessen surface wind so we have included low-level wind shear in the TAFS. Mixing and dry advection should result in VFR conditions after 14z. The GFS LAMP and NAM Bufkit momentum transfer tool supported gusts 15 to 20 knots after 14z. EXTENDED AVIATION OUTLOOK...Expect widespread restrictions Wednesday and Wednesday night as another strong system crosses the region with thunderstorms which may be severe. It will likely be breezy Thursday through Friday. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...Lake Wind Advisory until 4 AM EDT Tuesday for GAZ040-063>065- 077. SC...Lake Wind Advisory until 4 AM EDT Tuesday for SCZ015-016-018- 020>022-025>031-035>038-041. && $$ SYNOPSIS...99 NEAR TERM...99 SHORT TERM...99 LONG TERM...99 AVIATION...99
Area Forecast Discussion
National Weather Service Peachtree City GA
1059 PM EDT Mon Apr 3 2017 .UPDATE... After a busy day of severe weather...conditions have quieted down this evening and this trend will continue through Tuesday. Have adjusted POPs to keep up with current trends...largely coinciding the most recent HRRR solutions. Have also been adjusting temps/cloud cover as necessary. Latest analysis of the mid levels indicates that the negatively tilted shortwave trough /responsible for today`s squall line/ has pivoted into the OH Valley/Midwest. A weak shortwave is currently rotating amidst the broad cyclonic circulation associated with this trough and was located over northern AL/south-central TN as of 03z. Synoptic lift with this wave has triggered convection across this general area and it is not out of the question a few cells could move into or develop across far north Georgia over the next couple of hours. Although shear/helicity are still high...lack of sufficient CAPE argues for weaker updrafts and at best the potential for some gusty winds as the main threat with these cells. Should begin to clear out tonight. Some patchy fog is not out of the question...especially across central Ga...but winds will likely remain too elevated to warrant mention in the grids at this time. Tuesday still looks pleasant in the wake of the cold frontal passage. Wednesday system is still a concern in terms of severe weather. Kovacik && PREV DISCUSSION... /Issued 349 PM EDT Mon Apr 3 2017/ SHORT TERM /Tonight through Tuesday Night/... Current regional radar loop shows the main line of severe storms moving east across the state and should exit our eastern CWA with in the next hour. There are still some showers and thunderstorms behind the line but they are much weaker. All in all things are winding down across our CWA but these storms are expected to continue as they push into SC. As the rain ends this evening we will keep some clouds over the region then begin to clear out around 2am to 4am Tuesday morning. Should see mostly clear skies across the region Tuesday with day time highs in the 80s. Precip begins to move back into the forecast area from the west as the next frontal system developing over the central and southern plains Tuesday pushes its frontal boundary into SW GA Late Tuesday in Wed morning. 01 LONG TERM /Wednesday through Monday/... No changes have been made to the extended. Wednesday still on track for another round of strong to severe storms. Previous discussion is included below. 41 PREV DISCUSSION... /Issued 347 AM EDT Mon Apr 3 2017/ LONG TERM /Tuesday Night through Sunday/... Another round of wet and stormy weather is in the cards Wednesday into Wednesday night. This due to a strong cold front forecast to move across the area Wednesday night and associated with a sharp upper level trough moving across the mid U.S. The airmass becomes unstable quickly on Wednesday ahead of the front as warm moist air moves over the area. Low level wind shear increases as well in the 30-45 kt range. This will lead to an Enhanced risk of severe storms. Storm potential will end quickly Wednesday night with the cold front passing. The only concern then will be shower chances from wrap-around moisture in the upper level trough Thursday into Friday. Temperatures could get cold enough for a rain/snow shower mix for the higher elevations of the mountains late Thursday night/early Friday. Saturday and Sunday will be dry as high pressure moves across the area. Temperatures are expected to be above normal until the cold front moves through Wednesday night then temperatures will cool off to below normal until about Sunday. Friday and Saturday mornings will be the coolest with lows in the 30s and 40s. BDL AVIATION... 00Z Update... Storm complex that brought thunderstorms to the TAF sites has largely cleared the area. Biggest concern in its wake will be the potential for MVFR/IFR cigs overnight tonight along with some patchy fog...mainly across CSG and MCN where rains have been most recent. MVFR/IFR cigs likely across all sites tonight...with clearing at all sites by sunrise Tuesday. Tuesday looks pleasant...with increasing cirrus and perhaps a few afternoon cu. Winds will remain on the SW side tonight...with gusts dying down after sunset but remaining sustained towards 10kts. Winds likely to flirt with or briefly shift northwest Tuesday morning before returning southwest again around 10kts Tuesday afternoon. //ATL Confidence...00Z Update... Medium on timing/coverage of MVFR/IFR cigs High on all other forecast elements. Kovacik && .PRELIMINARY POINT TEMPS/POPS... Athens 70 56 82 58 / 90 10 0 10 Atlanta 68 58 81 60 / 90 10 0 30 Blairsville 64 52 75 52 / 100 20 5 10 Cartersville 68 55 80 57 / 100 10 0 20 Columbus 74 60 84 62 / 90 10 5 30 Gainesville 66 56 78 57 / 90 10 0 10 Macon 76 59 84 60 / 90 10 5 20 Rome 68 55 80 56 / 100 20 0 20 Peachtree City 69 55 82 57 / 90 10 0 30 Vidalia 84 64 85 64 / 100 70 10 20 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Kovacik LONG TERM....Baker AVIATION...Kovacik
Area Forecast Discussion
National Weather Service Wilmington NC
851 PM EDT Mon Apr 3 2017 .SYNOPSIS... Showers and thunderstorms will move across the area this evening into tonight ahead of a cold front and some of these storms could be strong to severe. Dry and warm weather will follow for Tuesday and early Wednesday. Another storm system and cold front will bring renewed thunderstorm chances late Wednesday into early Thursday. Cooler and drier high pressure will build in Friday into Saturday, with a warming trend starting early next week. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... As of 850 PM Monday...Updated forecast to cancel Severe Thunderstorm Watch. Last of the strong convection is in process of moving offshore the Cape Fear Region. Previous discussions follow: Strong convection racing across the forecast area faster than high-res guidance has forecast. Expect the worst of it will be offshore most places before 9 PM, followed by a bit of light stratiform rain, then stratus and some patchy fog. Damage reports have fortunately been few and far between. Will be updating forecast to reflect accelerated end to this event. Previous discussion from this afternoon follows: Winds will continue to veer around and increase through this afternoon as coastal trough lifts north and a frontal system makes its way east. This will help to increase low level moisture with dewpoint temps making there way into the 60s. A line of strato cu and spotty showers associated with coastal trough have shifted north leaving plenty of sunshine to destabilize the atmosphere. The spotty showers left higher dewpoint in their wake, while the rest of the area had readings in the mid 50s. Temps well into the 70s to around 80 most places will remain warm into tonight. A potent storm system will lift northeast towards the Great Lakes through tonight. An associated well defined squall line has been marching across the south and will reach into the Carolinas early this evening. SPC continues to highlight the potential for severe weather into tonight with watches issued associated with the squall line upstream into SC this aftn. Best chances will be inland, especially across inland SC. Initially a warm front will lift north leaving warm and increasingly moist air in its wake. Gusty southerly winds ahead of the front will remain strong behind it with a strong low level jet up to 50 to 60 kts. The earlier arrival of the convection will leave a more unstable atmosphere and greater potential for stronger to severe storms through this evening. The latest HRRR show the line arriving to our W-SW portion of forecast area between 6 and 8 pm and then holding together quite well as it traverses the area toward the E-NE reaching the coast between 9 and 11 pm. Also shows some lingering cell development behind the squall overnight. The greatest upper level support is aligned with squall line, but shortwave energy and decent jet dynamics linger into the overnight hours to support this. The greatest QPF will also be aligned with squall line, but cells developing ahead and behind the line could also produce a quick quarter of an inch or so. The total rainfall should range between 1 to 2 inches most places. Clearing will occur from west to east through the morning hours on Tuesday. A deep west to southwest flow will leave plenty of warm air over the region but dewpoint temps will begin to drop through the afternoon as front moves off to the east. Overall expect plenty of aftn sunshine with temps reaching well above normal after a very warm start to the day. Temps will drop initially this evening, especially in convection that moves through, with overnight low this evening and plenty of WAA to stabilize or push temps a little warmer through the night. With temps close to 70 at daybreak expect a rise into the 80s Tues aftn. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... As of 300 PM Monday...Very warm temperatures this period will be followed by yet another strong impulse and possible severe weather event late Wednesday into Wednesday night. Initially, surface high pressure will be offshore, and mid-level ridging will be amplifying in response to a strong shortwave digging through the middle of the country. This will create a very warm Tuesday night with lows dropping only to around 60, followed by an equally warm Wednesday with highs in the 80s. Clear sky conditions are expected through Wednesday aftn with the exception of increasing high level cirrus, but the approach of a warm front will change that. This front is progged to lift across the CWA late Wednesday aftn into Wednesday evening, accompanied by increasing clouds and a good chance for tstms. As this front lifts north, instability and shear increase, and a chance for strong to severe tstms exists beginning with this feature. Behind this front, the CWA enters a broad warm sector ahead of a cold front which will cross offshore on Thursday driven by an anomalously deep upper trough. MUCape over 1000 J/kg will combine with strengthening LLJ (to 60+ kts) to produce an unstable and highly sheared environment capable of producing severe tstms. At this time, the strongest dynamics appear to stay just west of the CWA, and SPC has our Pee Dee counties in a SLGT risk, with MRGL elsewhere, but at least an isolated risk for damaging winds and a tornado exists late Wednesday through Wednesday night. Once again, the strongest instability is elevated thanks to a weak inversion at night, but could also be sufficient for hail, and all threats are possible. Additionally, WPC has the area in a MRGL risk for excessive rainfall this period, with training of storms in an environment with diffluent 500mb and 300mb flow combined with high PWATs supportive of very heavy rainfall in some locations. Convection will push offshore by daybreak Thursday, but cold advection lags until beyond this period, so mins will be warm Wednesday night, falling only into the low 60s. && .LONG TERM /THURSDAY THROUGH MONDAY/... As of 300 AM Monday...Cold FROPA Thursday morning will usher in very cool and dry air, bringing a cooling trend and dry weather into the weekend. Overnight minimums Thursday night through Saturday night will dip back in the 40s with highs Friday and Saturday only in the mid 60s. Monday will see temperatures rising back towards seasonal norms as the airmass modifies and a SW flow begins to set up. && .AVIATION /01Z TUESDAY THROUGH SATURDAY/... As of 00Z...Primary threat to aviation interests this evening is a line of showers and thunderstorms racing across the forecast area. This line will be offshore by around 9 or 10 PM and has already moved past our inland terminals. Strong gusty southerly winds will continue into tonight with higher gusts through this evening. Patchy strato cu and cirrus will produce intermittent MVFR/IFR this evening after convection moves east of the terminals. Expect VFR all terminals after daybreak on Tuesday. Extended outlook...Chance for MVFR/IFR late Wed thru early Thu from convection ahead of a strong cold front. Possible MVFR from showers Thu night thru Fri. Strong synoptic winds in excess of 25+ KT gusts possible Tue and Thu. && .MARINE... NEAR TERM /THROUGH TUESDAY/... As of 730 PM Monday...Small Craft Advisory remains in effect as dangerous conditions continue over the coastal waters. Most immediate threat is a line of showers and thunderstorms now moving offshore our SC waters, followed a little later this evening by the waters off of the Cape Fear region. Previous discussion from this afternoon follows: Small craft advisory conditions on target for this evening into tomorrow. Strong and gusty southerly winds have increased through this afternoon and will remain strong through tonight. South to southwest winds will peak in the 25 to 30 kt range late tonight. There is potential for much higher gusts within any storms that move across the waters. Cold front does not reach the waters during the period and winds will remain out of the south or southwest into Tue. Seas currently 2 to 3 ft will respond to increasing southerly flow later today, building to 4 to 6 ft by early evening and peaking near 10 ft as the period ends. SHORT TERM MARINE/TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/ As of 300 PM Monday...Decreasing SW winds will ease to around 10 kts by Wednesday morning before shifting to the NW as a weak boundary shifts offshore. This period of NW winds will be short lived and light, as a warm front lifts north across the waters during Wednesday bringing a return to southerly winds. By Wednesday night, speeds will ramp up to 15-25 kts, and the period will likely be bookended by SCA`s. After seas fall from 3-6 ft very early Tuesday night to 2-3 ft much of Wednesday, they will ramp back up to 5-8 ft late in the period. Widespread showers and thunderstorms are possible Wednesday night as well, with locally higher winds and seas, along with torrential downpours and cloud to sea lightning. LONG TERM /THURSDAY THROUGH SATURDAY/... As of 300 AM Monday...Expect advisories will be in place into Friday as strong SW to W winds continue. Conditions will moderate on Friday night and Saturday as high pressure moves in from the west. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...Small Craft Advisory until 11 PM EDT Tuesday for AMZ250-252- 254-256. && $$ SYNOPSIS...RGZ NEAR TERM...REK/RGZ SHORT TERM...JDW LONG TERM...REK AVIATION...REK MARINE...REK/JDW/RGZ
National Weather Service Jackson KY
1005 PM EDT Mon Apr 3 2017 .UPDATE... Issued at 1005 PM EDT MON APR 3 2017 First of two broad lines of scattered convection is just entering our area from the west. Thus far the HRRR has been handling the trends in convection fairly well through the early evening. That being said expectations are that the line will weaken and break up a bit in the north and intensify a bit across the central and southern portions of the area. Maintained likely to low categorical PoPs through the remainder of the evening into the early morning based on radar trends and the HRRR. GOES IR seems to support this scenario as well with the regional loop indicating occasional cloud top cooling with the cells in the south as they pulse in a cyclical fashion and a hint of some warming with cloud tops along the northern portions of the line as storm cells get closer to our Blue Grass. Updated the grids for latest thoughts and to bring grids in line with sfc obs. Also freshened up the zones for evening wording. UPDATE Issued at 811 PM EDT MON APR 3 2017 Forecast is generally on track. Did make some adjustments to the grids for short term trends, such as some temporary clearing. Otherwise brought hourly temps and dew points in line with recent observations. Line of convection to our west continues to push eastward and should be on our doorstep within the next two to three hours. At present there are generally two broken lines of activity. The first line moving through central Kentucky is showing some signs of weakening. HRRR showed something similar and the more recent runs have generally shown the same thing, except with some intensification after activity move into our forecast area. Inherited likely PoPs seemed reasonable so decided to maintain them along with Isold thunder. && .SHORT TERM...(This evening through Tuesday night) Issued at 405 PM EDT MON APR 3 2017 Surface analysis shows a warm front advancing NE across the area and a few showers and perhaps a storms could pop in the Bluegrass this evening. This as CAMs continue to indicate this, however not seeing much developing in the west this hour. The bulk of the showers and isolated storms will progress east later this evening. The caveat that remains will be if any instability will can be seen this evening. In fact, the latest SPC Day 1 risk has pull the marginal risk out of the outlook. This seems reasonable given the lack of CAPE to support to environment. Did opt to keep the CAT POPs as most places will likely measure not the mention the better height falls this evening. There is good agreement that as this upper level and surface low eject northeast a dry slot will move into the region by dawn Tuesday morning. This will aid is POPs quickly fleeting by Tuesday morning and perhaps some sun by the afternoon. Decent mixing by Tuesday afternoon could also lead to some gusty winds in the afternoon of 15 to 20 mph in general. The clearing on Tuesday will lead to a temperature split overnight Tuesday. However, high clouds will be on the increase ahead of surface low and upper level trough in the midwest by Wednesday morning. .LONG TERM...(Wednesday through Monday) Issued at 504 PM EDT MON APR 3 2017 There is only one storm system to contend with during the period, but it`s a doozy, with a 979 mb surface low expected over western NY state by Thursday night. A shortwave trough currently over the southwest CONUS will amplify as it tracks east, phasing with additional troughing to the north. Surface low pressure in association with it is expected to start deepening over west TX tonight and Tuesday, and then track northeast to OH by Thursday, with development then taking the system further northeast. The circulation around the system is expected to draw warmer and more humid air north over our region on Wednesday, before the system`s cold front arrives. At this point, low level flow is expected to be downslope over at least the eastern part of the JKL forecast area, which would cut down on low level moisture, and hence instability. Our western counties would be less affected by this, and stand the best shot at thunderstorms and severe weather. In terms of severe weather, ample shear should be present, and the questionable ingredient is instability. The area is currently in a slight risk category by SPC, which seems reasonable. The cold front should pass through Wednesday evening, with a relative lull in precip for a short time after it goes through. However, comma head deep moisture under the upper low should rotate back into our area late Wednesday night into Thursday, with light rain and showers redeveloping. Models still differ as to how quickly it pulls out, and a blend is still being used for the forecast. It looks more likely that enough cold air will be drawn in before the precip ends that it will mix with or change to snow at times. For most of the area, temperatures will be too warm for accumulation, but the highest elevations near the VA border could see a bit. By the weekend, fair weather should return, but we will have a couple of cold mornings, with frost and/or freezing temperatures being a threat. Warmer weather should return to start the new week, as surface high pressure passes to our east and upper level ridging passes over. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) ISSUED AT 811 PM EDT MON APR 3 2017 A cold frontal boundary will push through the area tonight. Scattered showers and a few thunderstorms associated with the front are moving through western and central portions of the Commonwealth this evening. The initial wave of this activity should begin moving into our area from the west around sunset or a bit after. The initial line is showing some weakening at present. However, the HRRR did initialize fairly well with the ongoing activity and also suggests a trend of intensification as it reaches our area. Consequently did mention some thunderstorms in the vicinity of each terminal for about a 2 to 3 hour window as the main line transits our forecast area. Models also advertise a period of MVFR CIGS through the early morning time frame on Tuesday. This is associated with some lower cloud bases behind the front itself. Saw no reason not to follow along with guidance as this is typically the case. Winds will be generally out of the south, southwest until the front gets through the area. With FROPA winds will shift out of the west and become gusty for a few hours directly behind the front. Winds then slacken a bit through the remainder of the day Tuesday. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...RAY SHORT TERM...DJ LONG TERM...HAL AVIATION...RAY
Area Forecast Discussion
National Weather Service Melbourne FL
915 PM EDT Mon Apr 3 2017 .UPDATE... Tonight-Tue...Gradient wind oriented parallel to the peninsula has delayed a merger of the east/west coast sea breeze boundaries. Some interaction was likely occurring in north Lake and Volusia counties. This convection has been shallow as the interaction looks weak and we`ve lost daytime heating. These showers will diminish or push offshore before midnight. The HRRR model has been showing a band of convection dropping down out of north Florida at varying speeds. We have a slight chance for showers/storms in the far north just before/after 12z. The GFS is much less aggressive in dropping the band to the south and hangs up the remnant moisture band across our northern areas on Tue. There`s still time to monitor radar and short range model trends to fine tune the forecast of this feature. Whether the convection occurs Tue morning, or holds off until daytime heating, the chance for showers/storms looks to be mainly northward from about Kissimmee to Cocoa Beach. Little change planned to the current forecast. && .AVIATION... Low level southerly flow will keep the boundary layer well mixed so the prospect for fog is low though LAMP/MOS is highlighting some stratus toward daybreak. On Tue...winds will veer a bit out of the S/SW 10-15 knots and gusty turning onshore in a sea breeze during the mid to late afternoon at terminals south of the Cape. Timing of shower/storm chances is tricky but generally those that occur are expected to be northward from KISM-KMCO-KTIX. && .MARINE... Tonight/Tue...Marginally hazardous boating conditions indicated offshore north of Sebastian Inlet, due to a moderate-fresh southerly wind, where a small craft advisory is in effect into Tue morning. The pressure gradient is only forecast to ease a little into Tue afternoon, so conditions for small craft operation will remain poor across all of the waters. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...Small Craft Advisory until 10 AM EDT Tuesday for Flagler Beach to Volusia-Brevard County Line 20-60 nm-Volusia-Brevard County Line to Sebastian Inlet 20-60 nm. && $$ Forecasts...Lascody Impact Wx...Blottman
Area Forecast Discussion...UPDATED
National Weather Service Paducah KY
640 PM CDT Mon Apr 3 2017 .UPDATE... Issued at 640 PM CDT Mon Apr 3 2017 Updated the AVIATION discussion for the 00Z TAF issuance. && .SHORT TERM...(Tonight through Wednesday night) Issued at 106 PM CDT Mon Apr 3 2017 While no model is perfectly capturing ongoing convection, wrf and hrrr data appears a reasonable facsimile. Hrrr swings the action thru by about 02Z, with thunder threat diminishing thereafter. Troffy shower threat may linger into/thru the overnight, but Pops drop markedly. Synoptic modeling then gives a pause in Pops Tuesday, before bringing in another circulation system that pinwheels across the mid Mississippi valley Tuesday night-Wed. Both systems encounter similar airmasses and we are outlooked by SPC in a marginal risk svr for both time periods, mainly for isolated hail/damaging wind threat. Temps are warm with 70s/50s, but begin to get cooler/damper under the big trof/Low by Wed night, heading into the long term ptn of the forecast. .LONG TERM...(Thursday through Sunday) Issued at 243 PM CDT Mon Apr 3 2017 The medium range models were in good agreement in the extended forecast period. At the beginning of the period, lower mid level heights and cyclonic upper flow will prevail on Thu, with lingering showers east of the MS River during the day. Cool northerly flow aloft will continue just behind a low pressure system, with clearing skies and a northwesterly breeze at the surface. This will provide unseasonably cool temperatures on Fri, just like Thu, but with sunshine. Fri morning, if the wind lets up a bit, there may be patchy frost across parts of southeastern MO and southern IL, with temperatures in the 30s over much of the area. Sat morning, frost should be more widespread across much of the region, especially in the north, due to lighter winds. Afternoon highs are expected to rebound about 8-10 degrees by Sat, with a surface ridge axis passing through the PAH forecast area around noon. Southwesterly flow aloft and increasing southerly or south southwesterly low level flow Sun will encourage even warmer highs in the lower half of the 70s Sun and Mon. This will be in advance of deeper moisture and lift in our region associated with a vigorous low pressure system moving near the Canadian border. Thus, showers and possibly tstms will return to the forecast Mon. && .AVIATION... Issued at 640 PM CDT Mon Apr 3 2017 With the passage of a front, MVFR cigs/vsbys and TSRA at KPAH/KOWB early, possible MVFR cigs at KEVV/KOWB overnight, otherwise VFR conditions. Gusty southwest winds up to 18-20 knots will subside to AOB 10 knots after 06-07Z. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ LONG TERM...DB AVIATION...JP
Area Forecast Discussion
National Weather Service Mount Holly NJ
953 PM EDT Mon Apr 3 2017 .SYNOPSIS... Low pressure over Missouri will intensify as it moves into southern Ontario Tuesday morning. The associated warm front will move north into our region Tuesday with the cold front heading east, off the coast Tuesday evening. Weak high pressure briefly follows on Wednesday. Another intensifying low in the Ohio Valley Wednesday night becomes quite strong as it tracks across Pennsylvania on Thursday. It then drifts northeast over New England Friday and Saturday. High pressure eventually builds in from the west by Sunday. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... An upper air analysis this evening showed a trough from the Midwest to the Ohio and Tennessee valley`s. On the east side of this trough, several areas of focused 850 mb warm air advection is occurring including into our region. Meanwhile, surface low pressure is centered near Chicago with a warm front southeastward to North Carolina. As we go through the overnight hours, a southerly low-level jet on the order of 40-55 knots is forecast to overspread our area. This will drive increasing isentropic lift/ascent along with theta-e and warm air advections. The main forcing looks to be focused after 06z. It is during this time where much of the model guidance indicates an axis of increasing instability overspreading much of the area. This should be mostly elevated especially with a northern extent, however with a southerly flow temperatures may hold steady or rise some (after an initial drop due to lower dew points and rain to start) toward daybreak helping to boost some instability. As a result, we maintained isolated thunderstorms in the forecast during the late overnight hours. As the moisture increases and deepens, embedded convective elements will contribute to some areas of heavier rainfall. Given the low- level jet though, motion of the rain and any embedded thunder should be quick moving. The Flood Watch however remains as is (see the hydrology section below for more details). The hourly temperature, dew point and wind grids were adjusted based on the latest observations, then the LAMP/LAV guidance was blended in for the next few hours. No major changes were made to the low temperatures at this time, and the PoPs were adjusted based on input from the HRRR and radar/observational trends. The mention of the isolated thunder was delayed a few hours. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... Widespread showers should quickly depart most of our area during the early morning hours Tuesday as a warm front lifts across the area and the robust southerly low-level jet departs. Much of the area should get into the warm sector for a time, before a cold front sweeps through by about 18z. Boundary layer cooling looks to be delayed though as we await a surface trough or secondary cold front later in the afternoon. The forecast soundings indicate drying occurs with the initial wind shift, however some instability is also present through the afternoon. It will be a race between drier air and lingering lift and instability. How much sunshine breaks out during mid to late morning into the early afternoon will determine how much instability can be realized. As of now, looks like CAPE on the order of 500-1000 j/kg develops along with the K-Index approaching 30-35 and LI`s going negative. Therefore, we expect some showers and a few thunderstorms from late morning into mid afternoon. While severe thunderstorms are not anticipated, the forecast soundings are hinting at an inverted-v signature due to efficient boundary layer mixing in the afternoon which may result in locally strong wind gusts with some thunderstorms. The showers/thunder are expected to end toward the late afternoon as drier air moves in. Winds during the afternoon look to gust to around 35 mph at times more many areas given enough boundary layer warming and vertical mixing. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... **Potentially the biggest impact storm of the past 10 days for our area Thursday** 500 mb: Brief ridging occurs Tuesday night into Wednesday ahead of a developing large closed low that reaches western PA late Thursday, New England Friday and then rapidly weakens over the Maritimes next weekend. Very strong and very warm ridging follows early next week. Temperatures: Calendar day averages approximately 10 degrees above normal Wednesday, maybe again Thursday, near normal Friday - Sunday, then warming to 5 or 10 degrees above normal Monday. Forecast basis: the 330 PM forecast unless otherwise noted was a 50 50 blend of the 12z/3 GFS/NAM MOS Tuesday night - Wednesday night, 12z/3 MEXMOS blended 50 50 with the 12z/3 EC 2m t/td Thursday and thereafter the 15z/3 WPC guidance elements Thu night - Mon. The dailies... Tuesday night...from the mid shift: Westerly flow in wake of cold fropa that occurs late in the day Tuesday will promote drying across the region. a slight chance of showers early in the evening I-80 north. Breaks in the clouds should develop in the evening although CAA stratocu may yield a return of clouds later in the night (primarily N/W of the Fall Line). With the double-barrel low positioned to our north and northeast, the pressure gradient should be strong enough over the forecast area to continue a breeze through the night, especially with CAA helping to keep the boundary layer mixed overnight. Wednesday...begins the third and last heavy rain event this week (31st, 4th and this last one focused on Thursday the 6th; we started this wet episode with an event on the 28th, so ultimately this should be the 4th and last in this series over the past 10 days). Partly sunny during the day with a west to northwest wind gusting 20 mph and above normal temps in the 60s to around 70, but cooling sea breezes developing during mid or late afternoon along the coasts. Showery rains develop from southwest to northeast later at night with min temps 10 to 15 degrees above normal. Thursday...STORMY! Widespread moderate to locally heavy showery rains with a band or two of thunderstorms, some of which may be severe on the Delmarva into S NJ between 6 AM and 2 PM, when TT rise into the lower 50s, MLC increases to 500J or greater and very strong 0-3K and 0-6K shear develops, along with SWI subzero. These storms will probably be remnants of potential strong or SVR tstms racing newd from the Carolinas and e VA. For our area: Damaging winds would be the primary threat but a conditional tornadic threat may exist with models showing backed flow near the warm front/ negatively-tilted trough axis. Thursday night...There may be a temporary lull in the showery pattern Thursday night once the surface low passes to our north into NYS. Friday...Upper low crossing the area should yield periods of wrap around showers and sprinkles, most common nw of I-95. There is a small chance mixed with wet snow over the Poconos and extreme northwest NJ above 1500 feet. Saturday...Considerable cloudiness then becoming partly sunny by days end. Saturday night...Possible radiational cooling. Small chance frost advisories may be needed for our MD and DE counties where the growing season is already active. However, as of this afternoons forecast... chances are small. Sunday...Looks nice. Monday...Warm air advection. Eventually possibly a period of showers. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Through the overnight...VFR ceilings lowering to MVFR late this evening, then to IFR overnight as periods of rain overspreads the region. Some of the rain will be heavier at times mainly after 06z. A few thunderstorms are possible after 06z, however given the low coverage at this time a mention is not included in the TAFs. Southeasterly winds around 10 knots with some local gustiness at times, however southerly winds around 2000 feet are expected to increase to 40-50 knots ahead of a warm front. As a result, low- level wind shear is included starting later this evening and continuing through the overnight. Tuesday...IFR to MVFR to start as showers taper off for a time for most areas. As a warm front lifts northward conditions should improve to VFR by midday. Some additional showers and isolated to scattered thunderstorms should develop from near midday through mid afternoon, with brief MVFR/IFR conditions. South to southwest winds around 15 knots with gusts to around 30 knots (especially in the afternoon), becoming westerly toward late afternoon. OUTLOOK... Tuesday night...VFR with clearing skies during the evening. W winds with scattered gusts of 15 kt. Confidence: above average. Wednesday...VFR. W-NW winds gusting 15 to 20 possibly 20 kt early becoming light variable late in the day. Confidence: above average. Wednesday night and Thursday...VFR in the evening, lowering to MVFR and IFR as the next round of rain arrives. Rain will be heavy at times on Thursday with a chance of thunderstorms, especially in southern terminals. LLWS possible late Wednesday night and Thursday morning before a warm front arrives. Similar to Tuesday. Winds will probably gust 25 to 30 kt at times due to rapidly lowering sfc pressure and strong inflow. Winds in the warm sector Thursday afternoon on the Delmarva could gust 35 to 40 kt. Confidence in these values are low this far in advance? Otherwise Confidence: above average on the primary scenario described above. Thursday night and Friday...A brief lull in the precip may develop Thursday night. There would be an opportunity for improvement to VFR during this time. Chance of showers on Friday, which could result in localized MVFR conditions. southwesterly winds 10-15 kt with gusts to 25 kt, especially coasts. Confidence: average. Saturday...VFR cigs to start, then probably becoming VFR clear by night. Northwest winds gust to 25 kt during the day. Confidence: average. && .MARINE... The Small Craft Advisory for Delaware Bay has been started early as southeasterly flow (funneling direction) and resulting in gusts to around 25 knots already this evening. Small Craft Advisory remains across the area overnight through Tuesday. Winds will increase overnight and continue into the day Tuesday with gusts of 25-30 knots expected. Winds could gust around 35 knots for a brief period early Tuesday morning, which may be able to be covered by Special Marine Warnings since it may coincide with convection. Winds may diminish some Tuesday afternoon, but seas will remain elevated through the day. Rain will spread across the are tonight through early Tuesday morning. There could be a break in shower activity during the morning, but additional showers and some thunderstorms may be possible during the afternoon Tuesday. OUTLOOK... Tuesday night...SCA was extended into Tuesday night for the De waters. Winds decrease below 25 kt late. Wednesday...Winds and seas likely below SCA thresholds by Noon and no headlines anticipated...though we may need to advise for hazardous 5 foot seas during the morning. 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 some gale force wind transfer of 35-40 kt. Special marine warnings may also be needed where bands of showers and embedded thunderstorms imply concentrations of sfc wind momentum transfer. Friday...VFR cigs, with possible brief MVFR conditions possible in a shower. Southwest wind gust 15 to 25 kt. Saturday...VFR cigs clearing at night. Northwest wind gust 25 kt. && .HYDROLOGY... A Flood Watch is in effect overnight and continues through the day on Tuesday for central and northern NJ and for northeast PA. This NNJ area will be more susceptible to flooding with soils saturated and creeks and streams running high after recent heavy rainfall. Additionally, the majority of model guidance targets the highest QPF (1-2") in the watch area with the primary risk area, NNJ north of I- 78. There is a potential for our third and heaviest rain event in just a week`s period to occur on Thursday. One to two more inches is possible in 12 hours. The very wet antecedent conditions from earlier in the week will prime our region for additional flooding. MMEFS guidance shows some risk for minor or moderate flooding in our larger NNJ basins to extend into the weekend if the second and third heavy rainfall events materialize as currently outlooked. && .TIDES/COASTAL FLOODING... Since surface pressure will lower to about 985 MB near the surface low in PA, the associated tidal departures will increase considerably and some of our guidance is suggesting minor flood thresholds to be exceeded during the late afternoon high tide cycle along the NNJ Atlantic coast. 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. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...Flood Watch through Tuesday evening for PAZ054-055-062. NJ...Flood Watch through Tuesday evening for NJZ001-007>010-012>015. DE...None. MD...None. MARINE...Small Craft Advisory until 6 AM EDT Wednesday for ANZ450>455. Small Craft Advisory until midnight EDT Tuesday night for ANZ430-431. && $$ 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
912 PM MDT Mon Apr 3 2017 .UPDATE... Issued at 910 PM MDT Mon Apr 3 2017 Based on continued HRRR runs and NAM runs, have upgraded advisory to winter storm warning for lower elevations of the Spanish Peaks region. Also added eastern Las Animas to the advisories. /Hodanish UPDATE Issued at 630 PM MDT Mon Apr 3 2017 Based on latest HRRR runs and 3 km NAM guidance, added Pueblo and E Fremont counties to winter weather hilites. Precip in these regions should change to snow between 1 am and 3 am early Tuesday morning. The snow could be quite heavy as a band of heavier precip is likely going to develop from roughly the El Paso/Pueblo county line down towards south of Walsenburg, and this heavier band will push east. Some of the guidance is showing rather very heavy snowfall amounts over the lower elevations in the above mentioned areas, but believe melting due to the warm ground will hamper accumulations. I am quite concerned that if the snow falls heavy enough, we could see 2-3" of very slushy snow on ALL of the roadways which would make travel very difficult tomorrow morning. /Hodanish && .SHORT TERM...(This evening through Tuesday) Issued at 312 PM MDT Mon Apr 3 2017 Satellite images this afternoon showing the upper level trof over NV, with mstr and clouds spreading across CO. The upper trof is expected to move into the Four Corners area by about 06Z, and then close off a low that should track eastward across extreme northern NM through midday Tue and then into OK thru the afternoon. At the same time, an upper trof over western MT and ID is expected to drop southeast into WY tonight, phasing with the other upper trof. Currently there is some convective pcpn over southern portions of the forecast area, as expected. The HRRR shows pcpn increasing early this evening acrs the San Juan and La Garita mtns, and possibly across the southern San Luis Valley. Otherwise, the HRRR shows mainly just some isold to possibly scattered pcpn over the rest of the area through around 03Z. The HRRR also shows a front working its way south thru the southeast plains this evening, bringing gusty northeast to east sfc winds, and then develops more widespread pcpn acrs the plains behind this front thru 06Z...mainly from around Highway 50 and southward. Pcpn also increase before midnight over the rest of the mountain areas, but northern Pueblo and El Paso counties are looking fairly dry thru midnight. Pcpn then starts to spread north into these area after midnight and continues to be widespread acrs the rest of the plains, eastern mtns, central mtns and the Pikes Peak and Teller county areas. Both the HRRR and NAM are showing pcpn chances decreasing in the late night hours over about the southern two-thirds of the San Luis Valley. The best chances for accumulating snow look to be from around 5000 ft and higher, with areas below 5000 feet probably seeing a little bit of snow or a mix of rain and snow. The models are showing a decrease in the amount of pcpn over El Paso and Teller counties early Tue morning, especially southern portions, with gusty north winds. Although snow will still continue over the central mtns as well, that area will also likely see a decrease in the morning hours. The highest impact areas Tue morning are expected to be acrs the southeast plains from around Highway 50 and southward and along the Wet mtns and Sangres, especially the southern Sangres. The far southeast plains will likely see a mix or rain and snow, but some locations may just see rain. However, locations along the southern I-25 corridor are expected to see snow, and the fairly strong and deep northeast winds will likely focus the best accumulations in Huerfano and western Las Animas counties, including Raton pass. Central portions of the San Luis Valley may just see some light accumulations Tue morning, but areas near the valley edges may see high amounts. As the upper low starts to pull away from the area Tue afternoon, pcpn chances over the San Luis Valley will decrease or mostly end. They will also decrease over the southwest mountains and the eastern mtns, with only some light additional accumulations possible. The I- 25 corridor will also see a decrease in pcpn, but the far southeast plains will continue to see pcpn. Temps on Tue are expected to reach highs in the mid 30s to around 40 acrs the southeast plains and the San Luis Valley, while the Upper Arkansas River Valley should mostly see 30s. .LONG TERM...(Tuesday night through Monday) Issued at 312 PM MDT Mon Apr 3 2017 Tuesday night...Models indicate that the upper low pressure system will be located over the Panhandles Tue eve, and will quickly exit to the east through the night. Therefore, rain and snow is forecast to rapidly diminish across the forecast area by midnight, with cool and dry nw flow settling in by Wed morning. Assorted winter wx highlights for the eastern and central mts as well as for the Palmer Dvd last until midnight, which may be a bit long, but for now will maintain. Expect a cold night with min temps in the teens and 20s for most locations. Wednesday through Friday...High pressure ridging across the region will provide for about 3 days of dry conditions and gradually warming temps. Highs in the 40s and 50s on Wed, will climb into the 50s on Thu, then into the 60s to mid 70s for Fri as west-southwest flow aloft begins to increase. Saturday through Monday...A lot of variety when it comes to model solutions for the weekend and Monday. EC and GFS both indicate a longwave trough over the Pacific pushing onshore, and increasing moisture across the Great Basin and western Colorado by Fri eve. The GFS paints a quick-hitting system for Sat through Sun morning, then drying out on Mon. The EC, on the other hand, drops a slightly stronger disturbance further south on Sun, prolonging pcpn across the forecast area well into Mon. Given the variability, went with the extended procedure output of isolated to scattered pops over the higher terrain, more focused on the ContDvd over the weekend. Look for a very warm Sat with highs in the 60s for the high valleys, and 70s to near 80F for the e plains. Max temps cool about 5 to 10 degrees for Sun, then another 5 to 10 degrees for Mon. Moore && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 312 PM MDT Mon Apr 3 2017 VFR conditions are expected at KCOS thru probably late evening. Some showers may move into the VCNTY of KCOS late this evening, but chances for pcpn increase overnight, especially after 05Z with CIGS lowering into MVFR or even IFR and remaining that way thru midday Tue, and then improving some in the afternoon. KPUB should have VFR conditions thru mid to late evening, and then showers may move into the VCNTY and CIGS will lower into the MVFR category. By about 06Z, chances for showers will be high thru midday Tue and CIGS/VSBY may at times lower into the IFR category, conditions should improve during the afternoon hours. KALS may see showers in the area this afternoon, but chances increase this evening and CIGS will lower by mid to late evening. Chances for snow in the VCNTY look fairly high by around 04Z and continuing thru much of the night. By 12Z Tue chances for pcpn should decrease. MVFR conditions are expected from around 04z thru midday Tue with improving conditions in the afternoon. && .PUB WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until midnight MDT Tuesday night for COZ058>063-076-077-081-084. Winter Storm Warning until midnight MDT Tuesday night for COZ072>075-078>080-082. Winter Weather Advisory until noon MDT Tuesday for COZ069>071. Winter Storm Warning until midnight MDT Tuesday night for COZ087- 088. Winter Weather Advisory from 3 AM Tuesday to midnight MDT Tuesday night for COZ094. Winter Weather Advisory until noon MDT Tuesday for COZ083-086. Winter Weather Advisory until 6 PM MDT Tuesday for COZ065>067. Winter Storm Warning until 6 PM MDT Tuesday for COZ068. && $$ UPDATE...HodanishSHORT TERM...28 LONG TERM...MOORE AVIATION...28
Area Forecast Discussion
National Weather Service Raleigh NC
1120 PM EDT Mon Apr 3 2017 .SYNOPSIS... A potent upper level low lifting out of the southern Plains will cross the region overnight and Tuesday. Weak high pressure will build briefly over the area Tuesday night and early Wednesday, before another low pressure moves through the region Wednesday night and Thursday. && .NEAR TERM /OVERNIGHT/... As of 1120 PM Monday... Have adjusted the forecast to depict a lull in the precip as atmosphere has stabilized in wake of the departing convective band that crossed central NC late this afternoon/early this evening. Rain has cooled late evening temperatures in the 60-65 degree range. Still appears that we may see another round of convection later tonight as main trough aloft and attendant sfc front cross the region. While low level buoyancy is lacking, plenty of kinematics remain across the coastal plain with effective bulk shear 40-50kts. Low level air mass expected to destabilize in response to mid level lapse decreasing in response to s/w aloft. The destabilization and approach of the sfc front should trigger scattered convection with an isolated low topped supercell possible, suggested by good turning in the lowest 3k ft. Overall convective coverage no worse than scattered and primarily confined to locations east of highway 1, more so I-95 and east. Will note that successive runs of the HRRR have trended with weaker intensity and less coverage. && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... As of 340 PM Monday... The effective front will have moved offshore by early Tuesday, while the main cold front lags west of the mountains and doesn`t really push into the area until early Wednesday. Thus westerly flow and an airmass characterized by low level thicknesses of 1380m will result in highs around 80, with wind gusts to 25-30kt. The synoptic cold front is forecast to push into NC from the north Wednesday night, but the airmass change is delayed and lows will be mild in the lower 50s. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... As of 315 PM Monday... Wed-Thu Night: Dry conditions are expected in the wake of the cold front Tuesday night through at least noon Wed. Cloud cover will increase from the SW during the day as upstream convection outruns the primary forcing (upper level low and associated cold front) into GA/SC (similar to today). The aforementioned convection is progged to propagate downstream into W/SW portions of NC by mid/late afternoon, affecting the SW Piedmont by 21-00Z, progressing NE through the remainder of central NC between 00-06Z Wed evening/ night. Expect increasing cloud cover to result in slightly cooler temps in the W/SW Piedmont, with highs ranging from the mid 70s (W/SW) to lower 80s (SE). A short lull in precipitation will be possible in the wake of the first round of convection Wed night, however, additional activity will likely accompany the cold front progressing eastward into the region Thu morning as shortwave energy rounding the base of the upper level low (tracking NE from the central MS river valley to the lower Great Lakes) ejects NE into the Carolinas 12-18Z Thu. Expect lows Wed night in the mid 50s (W) to lower 60s (E). Although diurnal timing of the frontal passage will be poor, strengthening deep layer forcing in the presence of steep mid-level lapse rates (assoc/w an elevated mixed layer progged to advect into the region from the SW) may compensate enough to support thunder along with a potential for severe weather. Expect precip to end from west-east by early afternoon as the cold front crosses the area, however, scattered showers could re-develop late Thu afternoon (prior to the onset of CAA) as the upper level low tracks east across the northern Mid-Atlantic. Strong westerly winds will develop Thu afternoon as the MSLP gradient tightens over the region, becoming sustained at 15-25 mph with frequent gusts to 35mph. Although the equilibrium level will barely extend up to the -10C isotherm Thu aft/eve (suggesting thunder is unlikely), a low- end potential for damaging winds cannot be ruled out given steep 0- 3km lapse rates and strong westerly flow in the low/mid levels. Expect the potential for showers to end within a few hrs of sunset Thu evening as a drier airmass advects into central NC and upper level forcing shifts to the Mid-Atlantic/Carolina coast. Highs Thu in the 60s to 70F, warmest E/SE. Lows Thu night will be driven by CAA, in the low/mid 40s, coldest NW. Fri-Mon: Shortwave energy digging SE on the western periphery of the upper level low along progressing slowly offshore the Mid-Atlantic coast may result in a small potential for showers along/east of I-95 in the NE Coastal Plain Fri afternoon. Otherwise, expect dry/cooler conditions with highs ranging from the mid 50s (NW) to near 60F (S/SE). The latest 12Z long range guidance suggests dry conditions will prevail this weekend and early next week as an upper level ridge builds over the eastern US. Expect high temperatures to gradually rebound over the weekend, reaching the 70s again by Mon. Although lows may dip into the upper 30s Fri night, a very dry airmass and W/NW breeze will likely preclude a potential for frost Sat morning. Winds will decrease by Sat night, and some potential for frost may exist Sunday morning, depending on the degree of airmass modification on Sat. -Vincent && .AVIATION /00Z TUESDAY THROUGH SUNDAY/... As of 730 PM Monday... 24-Hour TAF period: A line of showers and thunderstorms is currently moving through Central NC at 00Z. Rain has largely ended or will end shortly in the Triad (KINT and KGSO). The heaviest rain/thunder has just passed through KRDU and KFAY and will move through KRWI within the hour. As a result, visibilities have improved at the western terminals and will continue to do so as rain tapers off to the east. Still expect a period of visbys around 1SM-2SM at KRWI when the storms move through. Confidence on how long a return to VFR cigs will last, as many of the models indicate a chance for a period of cigs around 1-2 kft overnight. Dry air will take over from west to east around daybreak, resulting in a return to VFR conditions. Also, expect winds to remain strong and gusty through the period, initially south-southeasterly then veering around to more west- southwesterly overnight. -KC Looking ahead: VFR conditions are expected to last through Wed morning. Another low pressure system now over the Western U.S. will strengthen over the central part of the country then track to the ENE, dragging a cold front with sub-VFR conditions ahead of it into central NC starting Wed afternoon, with these poor aviation conditions persisting through Thu with numerous showers and storms and gusty winds. VFR conditions should return Thu evening, although winds will remain brisk and gusty through Thu night. VFR conditions likely Fri/Sat as the storm system moves off the East Coast. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...WSS NEAR TERM...WSS SHORT TERM...SMITH LONG TERM...Vincent AVIATION...KC/Hartfield
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Tuesday) Issued at 308 PM CDT Mon Apr 3 2017 19Z water vapor imagery Shows the upper low slowly lifting northeast into IL while a couple additional shortwaves dig southeast through the intermountain west, one over southern NV and the other over western MT. At the surface, an area of low pressure was noted over the middle MS river valley with a broad area of high pressure over the northern plains. The forecast for tonight calls for a break from the rain before the next round moves in on Tuesday. There is a weak perturbation propagating across NEB with an area of showers across north central NEB. The HRRR thinks there could be a few showers along the state line this evening so have kept a small POPs across the northern Counties this evening. Visible imagery shows a Cu field across north central KS within an area of low level convergence. So while the southern extent of the shower activity across NEB as retreated, think there is still some potential for an isolated shower. Lows tonight should be in the lower and middle 40s aided by some partly cloudy skies. For Tuesday, the next upper low if progged to become better organized with PVA and upper level difluence increasing through the afternoon. The expectation is for isolated showers in the morning to become more widespread by the afternoon as the dynamics improve through the day. Models are continuing to show the track of the surface low to be just southeast of the forecast area keeping a north and east wind over east central KS. As a result, the models keep the stronger instability to the south of the forecast. Although some elevated instability of a couple 100 J/kg is still possible over east central KS. So there should be some thunder with the showers, but any severe threat looks to remain south of the area. Highs Tuesday should be cooler with clouds and precip likely through the afternoon. So have kept the forecast for middle and upper 50s going for much of the area. Parts of Anderson CO could sneak into the lower 60s. .LONG TERM...(Tuesday night through Monday) Issued at 308 PM CDT Mon Apr 3 2017 The final major upper low forecast to track directly over northeast Kansas Tuesday night and Wednesday bringing a strong deformation zone and band of rainfall over northeast Kansas. Forecast totals are from a half to in upwards of an inch across the CWA, resulting in total qpf amounts tomorrow through Wednesday from half of an inch to an inch and a half of rainfall. Could easily see higher totals with any convective driven rainfall. And given the continuous days of rainfall, the potential for flooding continues to increase. Highest totals were concentrated towards east central KS where model guidance is fairly similar between the NAM, ECMWF, and Canadian models with the upper low centered a bit further south. Wednesday morning will overall be a wet and cool afternoon with highs in the 50s. Precipitation gradually clears by the evening with dry conditions returning for most of the week. A 1028 mb sfc high spreads southward in the systems wake Thursday and Friday morning, bringing near freezing temps to the region. Current forecast lows has middle 30s in the 34-38 range so have mentioned the potential for patchy frost. Shortwave ridging builds in the central conus Thursday onward as the next upper trough slowly deepens off the western CONUS. Towards the sfc, induced troughing over the western high plains returns the southerly flow and warmer temperatures. Highs in the 70s are expected Saturday and Sunday with sunny skies and winds gusting in upwards of 20 mph. As the upper trough deepens as it swings over the northern plains, a frontal boundary will bring back chances for showers and thunderstorms as early as Sunday afternoon. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 629 PM CDT Mon Apr 3 2017 VFR conditions are expected through the rest of the afternoon and the first half of tonight, with MVFR cigs overspreading the area towards sunrise and persisting through the day with periods of IFR conditions. Aside from some isolated light showers towards MHK this evening, the next chance of rain arrives during the day tomorrow, with the better chance of rain coming after 18-21Z tomorrow. Patchy fog may also develop tonight ahead of the low clouds, but confidence was not high enough to mention in the TAFs. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Wolters LONG TERM...Prieto AVIATION...Skow
Area Forecast Discussion
National Weather Service Albuquerque NM
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 && .AVIATION... 18Z TAF CYCLE Closed upper low moving eastward through northeast NM this afternoon and into west TX after 05/00Z. Areas of mt obscurations in MVFR to IFR cigs/vsbys in precipitation/br/fg and isold tstms will prevail mainly northeast of a Dulce to KABQ to KCVN line through 05/0Z. Lcl LIFR/VLIFR condtions are likely across far northeast NM through approximately 04/23Z including KRTN and KCAO. Scattered snow showers will continue in the northern mountains btwn 05/00Z-05/06Z. Strong north winds will push southward along and behind a backdoor cold front through the eastern plains during the afternoon and early evening. A dry north to northwest flow aloft moves in after 05/06Z. 33 && .PRELIMINARY POINT TEMPS/POPS... Farmington...................... 21 59 29 68 / 0 0 0 0 Dulce........................... 19 55 23 64 / 20 0 0 0 Cuba............................ 22 54 28 64 / 10 0 0 0 Gallup.......................... 17 60 21 69 / 0 0 0 0 El Morro........................ 18 58 21 67 / 0 0 0 0 Grants.......................... 19 60 22 69 / 0 0 0 0 Quemado......................... 24 61 31 70 / 0 0 0 0 Glenwood........................ 32 72 34 78 / 0 0 0 0 Chama........................... 14 49 21 58 / 70 0 0 0 Los Alamos...................... 26 53 35 63 / 20 0 0 0 Pecos........................... 24 53 32 62 / 50 0 0 0 Cerro/Questa.................... 16 50 22 59 / 60 0 0 0 Red River....................... 16 38 19 51 / 70 0 0 0 Angel Fire...................... 18 39 18 51 / 70 0 0 0 Taos............................ 16 51 23 61 / 60 0 0 0 Mora............................ 20 51 29 59 / 70 0 0 0 Espanola........................ 25 59 32 69 / 30 0 0 0 Santa Fe........................ 26 54 35 64 / 30 0 0 0 Santa Fe Airport................ 24 58 30 68 / 20 0 0 0 Albuquerque Foothills........... 32 60 39 70 / 5 0 0 0 Albuquerque Heights............. 33 61 38 72 / 0 0 0 0 Albuquerque Valley.............. 29 63 34 74 / 0 0 0 0 Albuquerque West Mesa........... 32 62 37 72 / 0 0 0 0 Los Lunas....................... 29 64 34 74 / 0 0 0 0 Rio Rancho...................... 31 62 37 72 / 5 0 0 0 Socorro......................... 34 65 38 75 / 0 0 0 0 Sandia Park/Cedar Crest......... 25 54 31 65 / 10 0 0 0 Tijeras......................... 24 55 30 66 / 10 0 0 0 Moriarty/Estancia............... 23 57 28 68 / 10 0 0 0 Clines Corners.................. 23 56 31 65 / 20 0 0 0 Gran Quivira.................... 28 57 36 67 / 0 0 0 0 Carrizozo....................... 31 62 37 71 / 0 0 0 0 Ruidoso......................... 31 58 34 66 / 0 0 0 0 Capulin......................... 22 42 25 52 / 40 5 0 0 Raton........................... 23 48 26 59 / 30 5 0 0 Springer........................ 24 51 27 61 / 30 0 0 0 Las Vegas....................... 22 52 28 62 / 50 0 0 0 Clayton......................... 28 46 30 59 / 30 0 0 0 Roy............................. 26 49 28 61 / 20 0 0 0 Conchas......................... 32 59 36 67 / 20 0 0 0 Santa Rosa...................... 31 61 35 69 / 20 0 0 0 Tucumcari....................... 31 63 34 70 / 20 0 0 0 Clovis.......................... 32 61 36 72 / 10 0 0 0 Portales........................ 33 62 37 73 / 10 0 0 0 Fort Sumner..................... 33 62 36 72 / 10 0 0 0 Roswell......................... 35 66 37 78 / 0 0 0 0 Picacho......................... 33 61 38 73 / 0 0 0 0 Elk............................. 30 60 35 71 / 0 0 0 0 && .ABQ WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning until 10 PM MDT this evening for the following zones... NMZ510-512>515-527. High Wind Warning until 6 PM MDT this evening for the following zones... NMZ524-526-536-538>540. Winter Weather Advisory until 10 PM MDT this evening for the following zones... NMZ511-516. Wind Advisory until 6 PM MDT this evening for the following zones... NMZ507-521-525. && $$ 11
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
341 PM CDT Tue Apr 4 2017 .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 18Z TAFs... Concerns - MVFR clouds today - Rain starting tonight w/ t-storms possible late into early Weds - Cigs lowering to IFR and possibly LIFR - Increasing northeasterly winds - Mixed precipitation near RFD Aviation concerns initially are limited, but ramp up considerably later tonight and through the day Wednesday and even into Thursday. MVFR clouds will continue to stream southward this afternoon in wake of departing low pressure. High pressure behind this low will nose in from the northwest and will shift winds to north-northeast through tonight while the clouds then slowly lift. Focus will turn to a strong upper low across the Texas panhandle that will shift to the Great Lakes region Wednesday. Expect a band of showers to break out ahead of this low tonight. Instability is limited initially, but there could be a few thunderstorms late tonight into early Wednesday. The main push with this first batch of precipitation will be through midday. Snow may mix in near KRFD but it will be rain most areas and no accums are expected. Surface low pressure will strengthen through the period and shift to central Illinois Wednesday afternoon. Expect northeast winds to respond with gusts in the afternoon in the 30s. Expect off and on rain through the day. For the flying radar screen: Expect to see snow falling in some areas as early as later Wednesday evening, but will save those details for a future discussion. KMD && .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 Marquette MI
358 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 18Z TAFS through 18Z Wednesday afternoon) Issued at 130 PM EDT TUE APR 4 2017 Drier air mass that has spread over w and central Upper MI this morning will largely remain in place during this fcst period, allowing VFR conditions to continue at KIWD/KCMX/KSAW. Some stratocu is expected to develop Wed morning, but cloud bases should be above 4000ft. && .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...Rolfson MARINE...Rolfson
Area Forecast Discussion
National Weather Service Topeka KS
318 PM CDT Tue Apr 4 2017 .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 18Z TAFS through 18Z Wednesday afternoon) Issued at 1215 PM CDT Tue Apr 4 2017 A very active taf period will result in various flight conditions. MVFR ceilings may lift later this afternoon although drop back down to MVFR later this evening. Scattered showers will be likely this afternoon, but more widespread rainfall moves in this evening. There may be IFR ceilings after midnight especially at TOP/FOE. Periods of moderate to heavy rainfall is possible during the overnight. Late in the period conditions may improve as the rain moves off to the east. && && .TOP WATCHES/WARNINGS/ADVISORIES... Flood Watch from 7 PM CDT this evening through Wednesday afternoon for KSZ010>012-021>024-026-035>040-054>056-058-059. && $$ SHORT TERM...Sanders LONG TERM...Baerg AVIATION...Sanders