Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/31/19

National Weather Service Cleveland OH
1038 PM EDT Sat Mar 30 2019 .SYNOPSIS... A cold front across the area will continue to push southeast tonight, as a mid level disturbance tracks northeast along the front. A stronger upper trough will push east across the southern Great Lakes on Sunday. High pressure will build east through the southern Great Lakes and Ohio valley Sunday night. Ridging will remain in place across the local area through midweek. && .NEAR TERM /THROUGH SUNDAY NIGHT/... Issued a Winter Weather Advisory for portions of the Greater Cleveland area where we are trying to pinpoint higher snowfall totals. In particular, we are keying in on the area of heavier precipitation moving northeast out of Central Ohio. This is paralleling the rain/snow line meaning some areas will see heavy snow to the north and others moderate to heavy rain. Northwest Ohio and areas extending northeast along the lakeshore towards Cleveland have already transitioned to snow and heavy snowfall rates of 1 to 2 inches per hour are possible through 1 AM. Surrounding areas including the Mansfield/Ashland areas and points extending up the lakeshore can also expect several inches but not as much as Cleveland and Vicinity. The transition will be a little slower towards Erie, PA and parts of western Ohio where the air remains warmer aloft and this may cut into snowfall totals. Models also hinting at some increased lift and convergence downwind of the lakeshore which could contribute to some locally higher amounts. As for pure lake effect, we will not be cold enough until late Sunday morning but we do hold onto a cyclonic flow which contributes to the enhancement. Not out of the question that the Advisory may need to be expanded in time or area and will continue to monitor trends. Previous discussion... Challenging near term forecast this evening as a cold front bisecting the region, generally along the I-71 corridor this afternoon, sinks southeast across the area. A very potent mid level vort max over MO with an attendant coupled upper jet feature will lift northeast along/behind the surface front through the area tonight. A secondary mid level PV anomaly over MN will dig southeast towards the area tonight, moving east through the area on Sunday. High pressure will build east through the Ohio valley late Sunday through Sunday night. Through 00Z, a swath of widespread precipitation will work northeast across the area. This will provide moderate to at times heavy rain, especially along and south of the surface boundary. A few rumbles of thunder isn`t out of the question either given the strong upper dynamics, upstream lightning across the Ohio valley, and hi-res guidance indicating some weak instability working into the far southeast part of the CWA, mainly south of a Mt. Vernon to Youngstown line. Total rainfall amounts exceeding an inch to an inch and a half cannot be ruled out. The bigger question will be the transition to snow behind the front, as robust CAA works through the area and heavy precip aids in diabatically cooling the layer. The gamut of mid range and hi res guidance indicates the potential for impressive upward motion coinciding with the transition from rain to snow. Model soundings show saturation through the mid into the upper levels, with robust lift in the mid levels. Where this heavy precip is occurring and the boundary layer cools to below freezing through the layer, a corridor of heavy snow is expected to work east northeast across the area sometime between 03Z and 08Z. Guidance has been back and forth with the details, but the consensus is the heavier burst of precip will occur somewhere from Mansfield northeast into the primary snowbelt, especially across the higher terrain. Lake enhancement will aid in the snow across the snow belt this evening, with a gradual transition to primarily lake effect/upslope snow Sunday morning, before gradually ending through Sunday night. Now, there are several questions that dictate overall snowfall number overnight into Sunday. The main question is where will the heaviest precip coincide with the earliest transition to mainly snow? Also, how long will the heavy rates persist in any given location? To compound the issues of the timing of the changeover, surface temperatures will be marginally near or slightly above freezing as the snow starts. Currently thinking there will be heavy enough snowfall rates, a brief 1 to 3 hour window of 1 to 2 inch per hour rates, to overcome the warm ground/pavement temperatures and the marginal surface air temperatures to allow for some accumulating snowfall. There are many uncertainties that have led to only a slight uptick in snowfall amounts across the area from the previous forecast. Many hi-res guidance suites are painting solid advisory to even warning snowfall accumulations, however it is hard to say how much of an impact the warm ground/pavement will lead to overall compaction of the higher ratio snowfall shortly after the heavy precipitation ends. Also, somewhat concerned with a mid level dry slot noted moving into MO with the mid level impulse that could bring an abrupt end to the widespread synoptic post frontal precipitation. The latest HRRR runs are even picking up on this feature. Nevertheless, have went with a general 2-4 inch snowfall forecast from Mid-Ohio through the primary snow belt, with some local 5 inch amounts across the higher terrain of the snow belt, with the addition of lingering lake effect through the day on Sunday. Have decided to hold off on any headlines at this point, but trends will be monitored this evening and if the changeover looks to be happening sooner and the dry slot remains a decent distance away from the local area, there will likely need to be an upward adjustment in snowfall amounts and likely headlines. However, the confidence isn`t there right now. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... Broad troughiness will take place over much of the United States Monday through Tuesday. Although a weak ridge will extend north across the forecast area Monday allowing surface high pressure to build east across the Tennessee and Ohio Valleys. The surface high will then move off the east coast by Monday night. An upper level ridge will begin to build east into the eastern United States by Tuesday night. Fair weather will be the rule during this period as moisture streaming east across the Great Lakes Tuesday and Tuesday night should remain just north of the area in associating with a fast moving upper level positive vorticity maximum. Cold air advection expected during the early part of the week will begin to retreat and move east of the area Monday and Tuesday. So, warming temperatures are expected with highs on Monday in the lower to middle 40s followed by highs Tuesday upper 40s northeast to middle 50s elsewhere. Lows Monday night in the 20s warming to the middle to upper 30s Tuesday night. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... Broad upper level ridge will move east of the area Wednesday into Thursday allowing potent shortwave trough to race east across the Great Lakes region Thursday night and become negatively tilted. Another ridge will begin to build east over the area by Saturday. Surface high pressure firmly entrenched from the Georgia coast north to the Great Lakes will move east off the Eastern Seaboard Thursday night and Friday. As upper level trough becomes negatively tilted Thursday night, surface low pressure will move east out of the central Rockies and then deepen as it moves northeast into the central Great Lakes by Friday night. The storm system will tap into some Gulf of Mexico moisture as it moves into the area. This system will bring another round of rain to the forecast area. Rainfall amounts between 0.50" and 0.75" is possible with this system. Rain will pull out to the east late Friday night into Saturday. A gradual warming trend will take place as warm air advection occurs behind the high pressure moving off the east coast and in advance of the low pressure moving into the Great Lakes. Will stay conservative on high temperatures during this period due to the advancing cloud cover and precipitation chances holding temperatures down a tad. && .AVIATION /00Z Sunday THROUGH Thursday/... A cold front extends from near CMH to south of YNG at 00Z and will continue to move southeast tonight. Widespread rain is ongoing across the area with widespread IFR to low IFR conditions. As the air continues to cool behind the front this evening we will see rain transition to snow from west to east. This will coincide with a period of heavier precipitation to result in a swath of heavy snow extending from FDY-MFD-CLE. The transition will occur in these areas from 02-03Z before expanding east towards ERI in the 04-06Z window. Visibilities will likely drop to a 1/4 to 1/2 mile for a one to three hour window allowing for quick accumulations before precipitation ends or weakens. Lake enhanced snowfall will linger in the snowbelt later tonight and into Sunday. Northwest winds will also tend to increase this evening as the colder air arrives with many sites gusting to 20-25 knots. MVFR clouds expected to linger for much of the day on Sunday. OUTLOOK...Non-VFR possible into Sunday afternoon in snow showers, mainly at KCLE, KYNG and KERI. && .MARINE... Northwest flow will occur over the lake tonight through Sunday in the cold air advection. Winds 15 to 25 knots will cause small craft advisory conditions on the lake tonight and Sunday. Winds will begin to diminish Sunday night into Monday as the flow shifts around to the southwest by Monday afternoon. Otherwise, generally light winds expected through the middle part of the week. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...Winter Weather Advisory until 10 AM EDT Sunday for OHZ010>013- 020. PA...None. MARINE...Small Craft Advisory until 9 PM EDT Sunday for LEZ144>149. && $$ SYNOPSIS...Greenawalt NEAR TERM...KEC/Greenawalt SHORT TERM...Lombardy LONG TERM...Lombardy AVIATION...KEC MARINE...Lombardy
Area Forecast Discussion
National Weather Service Jacksonville FL
843 PM EDT Sat Mar 30 2019 .UPDATE... Sfc ridge is south of the area will continue to push southeast of the area tonight, as a cold front moves into the FL panhandle, central GA and SC by Sunday morning. JAX sounding continues to show dry airmass with PWATs of just under 1 inch, with satellite imagery showing some deeper moisture over srn FL and along the approaching cold front from lower MS Valley into central TN. Radar and satellite show sea breezes have merged inland this evening but noting only thin line of fair wx clouds. Otherwise, we are likely to see increasing high clouds tonight into Sunday morning. Sufficient low level moisture and light boundary layer winds will allow for some patchy fog. SREF and HRRR still suggesting this potential, in addition to low stratus, across the Suwannee Valley area. Little change was made to the fog area in the grids and min temps in the 50s tonight. && .AVIATION... VFR looks to prevail through at least late Sunday morning or early Sunday afternoon, except some chance of fog and/or stratus at KGNV after 09z until about 13z Sunday morning. With the cold front moving into the area Sunday midday time frame, have shown vicinity showers and a chance of t-storms after about 19z, with the frontal passage across the northeast FL terminals roughly 19z-23z, and a bit sooner at KSSI. Light winds tonight become southwest and west on Sunday around 10G20kt. && .MARINE... South-southeast winds near 10 kt this evening will veer to the south-southwest overnight and increase a bit. Seas 2-4 ft, 3-5 ft offshore look good. Little change in the current forecast. && .PRELIMINARY POINT TEMPS/POPS... AMG 58 76 47 56 / 0 20 10 30 SSI 60 77 50 57 / 0 60 30 60 JAX 58 82 53 60 / 0 90 40 70 SGJ 60 80 56 63 / 0 40 50 80 GNV 57 83 54 62 / 0 30 40 80 OCF 56 83 56 67 / 0 0 30 70 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$ Shashy/Sandrik
National Weather Service Jackson KY
1055 PM EDT Sat Mar 30 2019 .UPDATE... Issued at 1055 PM EDT SAT MAR 30 2019 A cold front continues to move across Eastern KY at this time. The boundary currently extends from Elliott County near Sandy Hook south to near Jackson to near Williamsburg. Wind gusts near and behind the front have been in the 35 to 45 mph range over much of Central KY into the western part of the CWA. With the potential for gusts over the next few hours until the front moves east of the area and the pressure gradient subsides, opted to issue an SPS. No lightning has been detected in KY for over an hour so opted to speed up the end of isolated thunder across the region. Some minor adjustments have been made to pops to account for recent radar trends with additional adjustments to winds and hourly temperatures. UPDATE Issued at 817 PM EDT SAT MAR 30 2019 Hourly pops have been trended toward recent convective allowing models, especially HRRR and HRRR time lag probabilities and radar trends. A cold front will move across the region late this evening into the overnight hours. Gusty winds should continue throughout the evening and into the overnight hours. A line of more intense showers and some strong to severe thunderstorms is ongoing over Central KY and middle TN near the front and this line should approach the region over the next hour or so and then progress east across the area. This line likely will weaken with loss of daytime heating, though trends will be closely monitored. Gusty winds will be the main concern with these. && .SHORT TERM...(This evening through Sunday night) Issued at 405 PM EDT SAT MAR 30 2019 18z sfc analysis shows the approach of the elongated low/cold front to our northwest. While we have been in the warm sector of this system all day, the convection has been mostly limited to points west and north of the JKL CWA through the afternoon. Gusty southwest winds of 10 to 20 mph with gusts up to 35 mph have certainly brought in warm air, as well. Temperatures soared into the mid to upper 70s across the area thanks to these winds and the thinning of the cloud cover over much of eastern Kentucky. Dewpoints stayed generally in the low 50s west to the mid 40s east, but with rising temperatures the humidity levels did fall into the 30 to 40 percent range. This has helped to contribute to a few new wildfires across the area this afternoon in addition to the ongoing ones in McCreary, Laurel, and Leslie Counties. SPC has raised the threat for severe thunderstorms later this evening as the front approaches with the Slight Risk category now touching the western fringes of the CWA and a much larger Marginal Risk area. This seems appropriate given the enhanced instability thanks to our warmer temperatures - though the SPC-HRRR is not much different from the earlier runs for later this evening across eastern Kentucky. The models are in good agreement aloft through the short term portion of the forecast. They all depict a descended node of the large North American trough swinging through the Ohio Valley and across Kentucky tonight. This will bring a healthy slug of mid level energy across the state initially through around midnight with a secondary surge passing by midday Sunday. The height falls move through the JKL CWA early Sunday morning with the whole system lifting off to the northeast later in the day. Heights will then rebound tepidly Sunday night and into Monday morning followed by more zonal 5h flow. Given the good model agreement will favor a blended solution with a strong nudge toward the CAMs and in particular the SPC HRRR for PoPs and thunder chances into the night. Sensible weather will feature an active evening across the area with the approach and passage of the cold front. Gusty southwest winds will diminish after sunset and then switch to the northwest as the front passes. A solid band of showers will accompany the front with a broken line of thunderstorms likely as they enter the CWA - weakening with its eastward progress. There is a chance for severe storms at the leading edge of these depending on how they develop over central parts of the state in the next few hours. Will continue to maintain the heightened wording in the HWO for this threat. The front then brings in much colder air after midnight on northwest winds. The air column many cool off enough for a touch of snow as the pcpn departs into Sunday morning - but with warm ground temperatures no accumulation is expected. Chilly conditions will be the rule for Sunday despite an afternoon return of sunshine for most places. The clearing skies then set up a very cold night with ridge to valley differences at play as well. With the start of the growing season underway will continue the freeze watch for our active counties into Monday morning. The CONSShort and ShortBlend guidance where used as the starting point for the grids with some significant adjustments to low temperatures Sunday night on account of favorable radiational cooling conditions for a moderate ridge to valley temperature split. As for PoPs, the only adjustments were to linger them a tad longer in the eastern higher terrain through mid morning Sunday. .LONG TERM...(Monday through Saturday) Issued at 245 PM EDT SAT MAR 30 2019 Most of the extended will see warm and dry weather associated with a large ridge of high pressure, which will be sprawled across the region from Monday through most of Thursday. Things will start off cooler than normal, however, as some colder air is expected to still be in place after a cold front pushes through the area tonight and Sunday. Monday will be the coolest day next week, with highs only forecast to make it into the upper 40s and lower 50s that day. After that, a steady warm up will take place. Highs on Tuesday will still be a bit below normal, but warmer than Monday, with max values in the upper 50s to 60 on tap across the area. From Wednesday onward, we can expect daily highs in the mid to upper 60s for most locations. A few readings may even reach the lower 70s on Thursday and Friday. We should see lows in the 30s Monday night and Tuesday night. Widespread frost will still be in place early Monday morning, but should melt off my mid morning. Temperatures are then expected to be much warm from mid week onward, with nightly lows in the 40s expected for the area. A few spots may only fall to 50 Thursday night. Our next good chance of rain will be from Thursday afternoon through Friday night, as a strong area of low pressure moves across the lower Great Lakes and Ohio Valley regions. A weather system passing to our south will bring scattered clouds to eastern Kentucky on Tuesday, but this system should remain far enough south of us to keep any precipitation out of the area. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) ISSUED AT 815 PM EDT SAT MAR 30 2019 Initially gusty south to southwest winds will be the main aviation concern to begin the period with gusts up to 25KT. A cold front will approach the area with showers along and in advance of it. A gradual decrease into the MVFR range is expected as showers and some thunderstorms arrive from west to east between 1Z and 5Z. Some brief IFR CIGS and or VIS is possible with the more intense showers. With this activity have included a few hours of VCTS and although localized gusts over 30KT are possible, confidence in that magnitude was too low to include at this time. Winds will become more west and then northwest rather quickly behind the front with gusts up to 25KT or so still possible. Winds and gusts should then gradually diminish between 6z and 12Z. As drier air moves in from the west, ceilings should improve into the VFR range between about 12Z and 16Z. && .JKL WATCHES/WARNINGS/ADVISORIES... Freeze Watch from Sunday evening through Monday morning for KYZ058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM...AR AVIATION...JP