Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/26/20

National Weather Service Albany NY
937 PM EDT Sat Apr 25 2020 .SYNOPSIS... High pressure will move east of New England tonight. A complex storm system will approach from the Ohio Valley for the second half of the weekend. Rain will overspread the region tomorrow mixing with and even changing to snow in the higher terrain areas for Sunday night into Monday morning, as a new low pressure system forms near Long Island. The higher terrain will have the better chance of accumulating snowfall, especially the southern Greens. The coastal low pressure system will continue to bring rain and higher terrain snow showers to start the week with cool temperatures for late April. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... As of 930 PM EDT, high/mid level clouds have overspread most of the region. Temps remain mild, generally 50s to around 60 within the Hudson Valley from Albany south to Poughkeepsie, with upper 40s to mid 50s elsewhere. Some sprinkles were noted across portions of northern PA and the southern/western Catskills, in association with a band of increasing mid level frontogenesis. This band of F-gen is expected to slowly track northward overnight and strengthen, possibly leading to an uptick in sprinkle/light shower coverage across portions of the eastern Catskills/Schoharie Valley through midnight, and the western Mohawk Valley into the Lake George/Saratoga region closer to, or just after midnight, and SW Adirondacks well after midnight. Otherwise, all else remains on track. Previous discussion follows... As of 410 PM EDT...High pressure moves east of New England and the Gulf of Maine early this evening, as the flow flattens briefly over the Northeast ahead of a strong mid and upper level short-wave approaching from the OH Valley. A jet confluent region sets up over northern NY and southeast Canada. High pressure builds in from south of James Bay. Clouds thicken and lower with increasing low and mid level warm advection across the region. The low-levels of the atmosphere remain dry, but the 3-km HRRR and NAM continue to show a lead band of warm advection pcpn moving across the eastern Catskills, western Mohawk Valley, the southern Adirondacks, and the Lake Region. This pcpn is driven by the isentropic lift should dry up east of the Hudson River Valley and produce mainly light rain or some very light snow above 2 kft AGL over the eastern Catskills and southern Adirondacks due to evaporative cooling. Lows tonight may be shortly after midnight, then slightly rise with lows in the upper 30s to lower 40s in the valley areas, and lower to upper 30s over the higher terrain. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... A Winter Weather Advisory has been issued from 8 pm EDT Sunday to noon Monday for the locations at 1500 feet AGL or higher in Bennington and western Windham Counties... Tomorrow...The primary closed compact low moves from the Ohio Valley to west-central PA and WV. Some short-wave energy shifts to the Chesapeake Bay corridor with a secondary cyclone forming in the late morning/early pm. Moisture gradually spreads north/northeast ahead of the complex system tied to the isentropic lift on the 290/295k surfaces. High pressure to the north will continue to funnel some low-level dry air southward. The column should gradually moisten with better dynamical lift and low-level jet segment pushing northward with the warm conveyor belt. PoPs were maintained in the likely and categorical range in the afternoon. SPC continues to scrape the southern most zones with General Thunder and with pockets of elevation instability indicated by the NAM/GFS with Showalter stability values near 0C, we will place a slight chance of thunder near the I-84 corridor. We called it periods of rain in the afternoon and some transition to wet snow is likely over the southern Dacks, and the southern Greens before nightfall with a coating to an inch or snow. Highs on Sunday will be in the upper 40s to lower 50s in the valleys, and 40s over the higher terrain. Sunday night...The guidance diverges with the role of the secondary low with the NAM keeping most of the pcpn going with the primary low, and a dry slot trying to sneak into locations from ALY south and east during this time frame. The GFS is further south with the primary and its closed circulation. We collaborated with WPC and WFO BTV and believe the 00Z and 12Z ECMWF are most on track with the placement of this Miller Type B system. The secondary cyclone scoots east of Long Island with a strong east to northeast LLJ with -U wind anomalies -2 to -4 STDEVs below normal. The favorable jet dynamics and this jet will help the pcpn to intensify in the mid to upper deformation zone for some snowfall over the southern Greens and southern Adirondacks. The cooling aloft with also allow for a transition to snow over the eastern Catskills, Helderbergs, northern Taconics and Berkshires. The dynamical and wet bulb cooling should allow for all snow above 1500 feet and it could be briefly an inch an hour over the southern Greens. We have total snowfall amounts above 1500 ft at 3-6 inches. We have generally 1 to 3 inches over the southern Adirondacks and 1-4" over the eastern and northern Catskills. 1-2" is possible over the northern Berkshires and northern Taconics. Some wet snowflakes are possible in the valleys with the Lake George and Glens Falls area getting a coating to a few tenths of an inch. The diabatic heating in the river valleys and the temps staying in the mid and upper 30s should prevent any snow accumulation. SLR`s were used in the 5-7:1 range over the mtns, and 3-5:1 range over elevations below 1500 feet. The dendritic growth zone remains high and pcpn intensity will play a factor. Again, the southern Greens have the best shot for the heavy pcpn. If the NAM is right on the northwest shift, then we may have to up totals in the southern Dacks. Lows will be in the upper 20s to mid 30s over the mountains, and mid/upper 30s in the valleys. Some sleet could briefly mix in over the western New England higher terrain too. The north to northeast winds will increase to 10 to 20 mph with some gusts around 35 mph. Monday...The fairly weak coastal low drifts to near Cape Cod and the broad closed H500 circulation remains over upstate NY and New England. Occasional rain and snow showers will persist over the forecast area due to the cyclonic vorticity advection and steep lapse rates. The late April sun angle should disrupt the shower activity and may it cellular with mainly rain showers in the afternoon. We only have the advisory going to noon time. Highs will only be in the mid 30s to around 40F over the mtns, and mid and upper 40s in the valleys. Monday night...The upper level low slowly shifts downstream with the rain and snow showers diminishing. Some light snow accums are possible over the upslope areas of the southern Greens and western Adirondacks with a coating to an isolated inch. Lows will fall into the upper 20s to mid 30s over the elevated terrain and mid and upper 30s in the valley with mostly cloudy conditions. && .LONG TERM /TUESDAY THROUGH SATURDAY/... Departing upper level disturbance east of the region will allow for shortwave ridging to build into the area for Tuesday. Any lingering morning clouds or sprinkles will give way to afternoon sunshine, with temps warming into the mid 40s to mid 50s. Continued dry and mainly clear conditions, along with light to calm winds, will allow for a chilly night on Tuesday night. Many spots will fall below freezing, with just the immediate Capital Region and mid Hudson Valley staying in the mid 30s, with upper 20s to low 30s elsewhere. Sky cover will be quickly increasing on Wednesday as the next storm system approaches and high pressure starts departing off to the east. This will be yet another large closed off upper level low approaching from the Ohio Valley. There still is some uncertainty regarding the exact speed of this system. POPs increase to CHC by afternoon and it may take until Wed evening or night for rain to begin across the entire area. With a strong southerly low-level jet ahead of the advancing storm system, there should be a period of steady rainfall, most likely for Wed night into Thursday. Some moderate to locally heavy rainfall can`t be ruled out, especially across the higher elevations, where upslope flow will enhance rainfall. With plenty of mild air, both at the surface and aloft, p-type will be all plain rain. Daytime temps should be in the 50s for most spots, with upper 30s to mid 40s at night. As the best isentropic lift shifts away, the steadiest rainfall will end for later in the week. However, plenty of lingering clouds and showers will continue for Thursday night through Friday, as the slow moving upper level low passes over the region. Will keep POPs fairly high for Thursday night into Friday with more rain showers. Drier weather, with temps closer to normal, should arrive for Saturday. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... Low pressure developing over the Ohio Valley will track northeast tonight into Sunday, as a secondary area of low pressure develops near Delmarva and tracks east northeast late Sunday and Sunday night. Clouds will thicken tonight into early Sunday morning, but flight categories will remain VFR. An band of sprinkles/light rain showers may develop around KGFL overnight, but there remains uncertainty if this precipitation will reach the ground. Therefore, will include a VCSH at this time. Steadier rain will then spread from south to north during the day Sunday, reaching KPOU in the morning, KALB/KPSF mid to late morning, and KGFL in the afternoon. At the onset of precipitation, cigs will start in the VFR range but trend down to MVFR for most sites (for Vsbys and Cigs). Periods of IFR could occur by late afternoon, especially at KPSF. Winds will become light/variable overnight, although may become southeast to south at KALB and increase to 5-10 KT with a few gusts up to 15-20 KT possible. On Sunday, winds will back from the southeast into the northeast by late morning, and will increase to 8-12 KT by afternoon, with some gusts of 15-20 KT possible. Outlook... Sunday Night: High Operational Impact. Breezy. Definite RA. Monday: High Operational Impact. Likely SHRA...RA. Monday Night: Moderate Operational Impact. Chance of SHRA. Tuesday: Low Operational Impact. NO SIG WX. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: Moderate Operational Impact. Chance of SHRA. Wednesday Night: High Operational Impact. Likely RA. Thursday: High Operational Impact. Breezy. Definite RA. && .FIRE WEATHER... High pressure will move east of New England tonight. A complex storm system will approach from the Ohio Valley for the second half of the weekend. Rain will overspread the region tomorrow mixing with and even changing to snow in the higher terrain areas for Sunday night into Monday morning, as a new low pressure system forms near Long Island. Cool and unsettled conditions continue for Monday. The RH values will increase to 70 to 90 percent Sunday morning, and then lower to 55 to 70 percent only Sunday afternoon with rain overspreading the region. The RH values will remain elevated at 90 to 100 percent Monday morning with rain and elevation snow persisting. The winds will light from the east to southeast at less than 10 mph tonight. They will increase from the east to northeast at 5 to 15 mph on Sunday. As the secondary low forms near Long Island, expect the winds to increase from the north to northeast at 10 to 20 mph with some gusts in the 25 to 35 mph range Sunday night into Monday. && .HYDROLOGY... Widespread hydrological problems are not expected prior to the middle of next week. There are two main storm systems that look to bring widespread precipitation to eastern NY and western New England over the next 7 days. The first will be a long duration event occurring late tonight into Monday with mainly rain for valley areas and rain transitioning to accumulating snow for elevations above 1500ft before turning back to rain or rain/snow mix. Total QPF or liquid equivalent for this event ranges between 0.75 and 1.25 inches. Some elevated river flows are possible, but no flooding is expected at this time. The second system may bring another long duration pcpn event that looks to arrive Wednesday night into Thursday. Guidance shows a plume of moisture rich air feeding into the Northeast allowing the steadiest precipitation to occur through Thursday with lingering wrap around showers possible into Friday. Since there are strong moisture connections out of the Gulf of Mexico and Atlantic, widespread amounts of 1 to 2 inches are possible with this second event and given that soils will likely still be saturated from the Sunday/Monday event, elevated river rises are expected and if terrain effects lead to locally higher amounts, then river responses will need to closely monitored. For details on specific area rivers and lakes, including observed and forecast river stages and lake elevations, please visit the Advanced Hydrologic Prediction Service /AHPS/ graphs on our website. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...Winter Weather Advisory from 8 PM Sunday to noon EDT Monday for VTZ013-014. && $$ SYNOPSIS...Wasula NEAR TERM...KL/Wasula SHORT TERM...Wasula LONG TERM...Frugis AVIATION...KL/Rathbun FIRE WEATHER...Wasula HYDROLOGY...Speciale/Wasula
Area Forecast Discussion
National Weather Service Bismarck ND
947 PM CDT Sat Apr 25 2020 .UPDATE... Issued at 947 PM CDT Sat Apr 25 2020 Model guidance is in pretty good agreement of fog developing in the James River Valley overnight due to the weak high pressure currently over central North Dakota, so added in patchy fog with this update. There is some indication that fog might expand further north to the Turtle Mountains. Only other change with this update was to increase cloud cover, as high clouds have begun streaming in across the west. UPDATE Issued at 643 PM CDT Sat Apr 25 2020 A few scattered rain showers continue to linger in the James River Valley area, but precipitation chances are quickly declining. We have yet to see any lightning with any showers in the forecast area, so went ahead and removed the chance for thunderstorms for this evening. No major changes to the forecast with this update, just blended in the latest observations. && .SHORT TERM...(This evening through Sunday) Issued at 212 PM CDT Sat Apr 25 2020 Critical fire weather conditions are possible in northwest North Dakota Sunday. This is where the greater potential for the lowest RH and stronger winds to overlap and a Fire Weather Watch has been issued. This afternoon, the synoptic pattern was characterized by a broad trough over the eastern CONUS, a ridge building over the Rockies, and a trough developing over the Pacific Northwest coast. Northwest flow was over the Northern Plains with an embedded shortwave trough placed over the eastern Dakotas. Scattered showers and possibly a few thunderstorms are expected to persist in the James River Valley counties into this evening before loss of heating and a weak surface high cuts off precipitation. Southerly flow develops overnight in our west as the aforementioned upstream and attendant surface low develop over southwest to south-central Canada. By Sunday morning, the frontal trough is expected to reach the Montana/North Dakota border with south/southwesterly winds in the prefrontal region to the east. As the surface low moves eastward through the day, dry westerly surface flow will fill in behind with sustained surface winds of 15 to 25 mph expected and clearing skies. As usual, the RAP continues to be the low- end of guidance for surface dew points...which has performed generally well in these dry post- frontal events. Blending the RAP with the NBM to create the relative humidity forecast, minimum RH values dipping into the teens in northwest North Dakota are expected. This, combined with the winds, puts conditions at near critical for fire weather Sunday afternoon and evening. The wiggle room in the forecast will be the relative humidities, with these events known to produce even lower RH values than forecast. Thus the Fire Weather Watch was issued with future shifts able to judge if an upgrade is necessary. In other weather potential, there will be a chance of showers along the surface trough, favoring the northern and central to eastern portions of the state where mid-level height falls to the north overlap with diurnal heating timing. Mid-level lapse rates look fairly meager so thunder was left out of the forecast for now. .LONG TERM...(Sunday night through Saturday) Issued at 212 PM CDT Sat Apr 25 2020 A chance of showers and thunderstorms is expected Monday evening with breezy northwest winds on Tuesday. Warming temperatures are then expected through the middle of the week. High pressure develops behind the frontal passage Sunday night and into Monday as mid-level heights build ahead of the next oncoming shortwave. Monday evening, a shortwave and surface trough are expected to move out of the northern Rockies and dive southeast through the Northern Plains through Tuesday. Showers and thunderstorms should accompany the frontal passage Monday evening beginning in the west and moving eastward overnight. Behind the front, winds will increase on Tuesday as northwest flow and modest pressure rises overlap in west/central North Dakota. Winds are currently sub- advisory criteria in the forecast, but will continue to highlight in the HWO as they`re still near criteria. The following several days are kept dry in the forecast as guidance is consistent in developing an upper level ridge over the Rockies and transitioning it eastward over the Northern Plains by Thursday evening. Ensembles have enough signal for a ridge breakdown and shortwave arrival Thursday evening to have chance PoPs. Otherwise, the pattern brings warmer temperatures with the NBM bringing highs in the upper 70s in the southwest on Thursday. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 643 PM CDT Sat Apr 25 2020 VFR conditions expected at all terminals through the 00Z TAF cycle. Scattered showers in the James River Valley are expected to end by 03Z. Cold front will move through the forecast area tomorrow, with winds transitioning from southerly to westerly at 15 knots, gusting to 25 knots. Some rain showers are possible in portions of northwest and central North Dakota, but only included at KMOT at this time, and even that is only marginal confidence. && .BIS WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch from Sunday afternoon through Sunday evening for NDZ001-002-009-010-017. && $$ UPDATE...MJ SHORT TERM...AE LONG TERM...AE AVIATION...MJ
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
626 PM CDT Sat Apr 25 2020 .DISCUSSION...Updated for latest aviation discussion below. && .AVIATION...VFR to MVFR conditions are expected through this evening, before generally VFR conditions return and persist through the remainder of the TAF period. There have been numerous storms southwest of the RGV in Mexico and there is a chance a few of these could make a run for the border late this evening through tonight. At this time, confidence is lower that any convection would make it to MFE, and even lower for any storms near HRL and BRO. Any tall CB across the west should be avoided as they may contain hail. && .PREV DISCUSSION... /issued 236 PM CDT Sat Apr 25 2020/ SHORT TERM (Tonight through Sunday Night): The weak cold front has started pushing into the northern Ranchlands this afternoon with a light to moderate easterly low level flow prevailing over the RGV. (Dewpoints north of a Baffin Bay to LRD line is in the 50s while south of this line dewpoints still remain in the upper 60s to lower 70s) This cold front is expected to edge through the rest of Deep South TX and the RGV later this afternoon and evening allowing for some generally drier air to finally filter into the region later tonight into Sun. The GFS is the coolest of the NAM/GFS/ECMWF trio with both the NAM and ECMWF temps coming in on the warmer side. Will lean closer to the NAM/ECMWF solution since the GFS is the current outlier. Pops are a bit tricky in the immediate near term forecast. The latest observed LAPS CAPE values show some pretty unstable CAPE (3000-4000 J/KG) pooling along the Rio Grande and just south of the river near and ahead of the approaching cold front. LAPS also currently shows pretty decent CIN values (100-200 J/KG) in place over Deep South TX and NE Mex limiting conv development. Accordingly, the immediate KBRO radar imagery shows no echoes threatening the RGV and Deep South TX. However, the latest HRRR and RAP model runs are persistent in developing conv over NE Mex as the cold front pushes up against the higher terrain there. Tha RAP guidance keeps most of the conv confined south of the Rio Grande while the HRRR tries to push some sct conv northwards across the western portions of the region. The short term NAM and ECMWF also is hinting at some isold/sct conv out west overnight into early Sun morning. So will maintain a mention of this mainly during the overnight hours. Since this appears to be firing after max heating and in the lower CAPE values north of the cold front, will not mention any potential for svr conv. However, an isold strong thunderstorm cannot be ruled out. The air quality may temporarily improve a little bit as the bulk of the particulate matter from the agricultural burning in Mexico will likely be shifted a little more to the S and SW out of the RGV. However, as the SE surface winds return Sun Night, expect the hazy/smoky conditions to return once again after this weekend. LONG TERM (Monday through Saturday): Fairly benign pattern to begin the long term period with generally zonal flow in place aloft and surface high pressure to the east across the eastern Gulf of Mexico and into the western Atlantic. Within the flow aloft, a couple of very weak perturbations move across Mexico into Texas but these should not affect the weather besides generating convection over the higher terrain of Mexico. Do expect for temperatures to run above average into midweek, especially on Tuesday and Wednesday. A developing storm system across the upper Midwest will likely result in breezier conditions on Tuesday. Winds then subside on Wednesday as a weak front advances across the region late in the day. This frontal boundary should provide a slight chance for rain and thunderstorms across Deep South Texas. This front could bump the temperatures down a couple of degrees for Wednesday night and Thursday. Otherwise, the temperatures will then rebound back to well above average levels with little rainfall as surface high pressure moves atop the region and a strong mid-level ridge develops across the Desert Southwest. MARINE (Now through Sunday Night): The low level surface flow across the lower TX Bay and Gulf waters will shift around from the E to the NE later this afternoon as the weak cold front moves steadily southwards. The PGF is not expected to increase significantly after the fropa, so do not anticipate drastic increases to the wind and swell activity through Sun Night. The marine conditions may briefly reach SCEC criteria later tonight into early Sun Morning mainly for the far offshore waters. The SE surface flow will then return pretty quickly later Sun into Sun Night. No SCA conditions expected through Sun Night for either the lower TX Bay and Gulf waters. Monday through Thursday night: Moderate to breezy southeasterly winds are expected early next week as the pressure gradient is expected to strengthen in response to a storm system across the upper midwest. Exercise caution to small craft advisory levels may be possible. Winds subside Wednesday into Wednesday night as a weak cold front advances into the region. This will shift winds out of the east-northeast. Winds return to out of the southeast into Thursday night. Seas improve but remain of moderate levels from Wednesday through Thursday night. && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ This product is also available on the web at: HTTP://WEATHER.GOV/RGV 56-Hallman...Aviation
Area Forecast Discussion
National Weather Service Quad Cities IA IL
802 PM CDT Sat Apr 25 2020 .UPDATE... Issued at 802 PM CDT Sat Apr 25 2020 The deformation axis of rain over north central Illinois continues to weaken and drift slowly eastward this evening. KDVN dual pol radar and MRMS are showing rainfall rates of less than a few hundredths of an inch per hour over southeast Bureau and Putnam counties over the past couple hours. At the current rate, the light rain or sprinkles should end over this area between 9 pm and 10 pm. With the threat of heavy rainfall over, the flood watch has been cancelled. && .SYNOPSIS... Issued at 254 PM CDT Sat Apr 25 2020 A rather pleasant or not so pleasant Spring day was seen today depending on where you were located. Clouds and rain kept points along and east of the Mississippi in the 40s, whereas some filtered sunshine and dry conditions were seen in the northwest sections of the CWA, with afternoon temps in the upper 50s and even low 60s. Breezy northeast winds were also seen. SPC mesoanalysis page and the 16z RAP model run showed the heavier fgen band nicely this morning in the 850-700 mb layer, which stayed mostly to the east of the CWA for much of the day. Estimated rainfall rates between 0.1" and 0.25"/hr fell for several hours with the highest 6-hr rain amounts per MRMS highest in Bureau and Putnam counties in IL, where three quarters to 1.50" fell. Fortunately, this was in a different location than the rain that fell prior to 8am this morning. && .SHORT TERM...(This Evening through Sunday) ISSUED AT 254 PM CDT Sat Apr 25 2020 Forecast focus in the near term is on precipitation exiting the area and cloud/temperature trends overnight. Tonight...Upper low will continue to push east into the Ohio river valley this evening and overnight, with associated def zone also moving east out of the area. Heavy precipitation has shifted east out of the initial flood watch area and thus have cancelled early for McDonough and Warren counties. An additional quarter to three quarters of an inch will be possible this evening in our far eastern counties and this may cause some ponding of water in fields in areas that already received over 1" of rain from this morning. After collaborating with neighboring offices, have issued an areal flood watch for Bureau and Putnam counties until 06z tonight to account for the additional rain. All precipitation should exit the area early Sunday morning with clearing skies. Sunday lows will drop into the upper 30s and lower 40s. With north winds remaining above 5 mph overnight and recent rainfall do not anticipate temperatures from dropping lower than forecast at this time. Sunday...warmer and dry conditions will be found, as a surface ridge moves overhead with plentiful late April sunshine. Forecast soundings show mixing up to at least 850 mb during the day, which will boost temperatures into the lower to middle 60s. This is closer to normal for this time of year. .LONG TERM...(Sunday Night through Saturday) ISSUED AT 254 PM CDT Sat Apr 25 2020 Monday and Tuesday Southerly flow ahead of two separate waves of low pressure will push warmer air into the region with highs in the 60s on Monday and mid 60s to low 70s (south) on Tuesday. Scattered light showers are possible Monday as elevated WAA/isentropic lift translates through eastern Iowa and northwest Illinois. Have rain chances between 20- 40%, and expect most areas to receive less than a tenth. On Tuesday, a much stronger mid-level wave is forecast to drop southeastward out of the Northern Plains and continue to dig into the Upper to Mid Mississippi Valley. A period of showers and thunderstorms is likely with this system with the best chances from late Tuesday morning into Tuesday night. It is too early to assess the risk for severe weather but it`s something to monitor. Some of the rainfall could be heavy as PWATs peak near 1.25 inches. Model consensus favors the eastern CWA with the heaviest rain, possibly 0.50-1.00"+. The track of the upper low will influence how far north a dry slot reaches later Tuesday night. The ECMWF is most aggressive on pushing it through our entire CWA. Wednesday Wrap around deformation rain is possible on Wednesday in a cold air advection regime, which could make for a raw day if the ECMWF verifies. Model blend temps are in the upper 50s to mid 60s and may need to be lowered in later updates. Thursday On Models in good agreement on a building upper ridge late in the week and drier looking pattern. Model blend highs are in the 60s for Thursday and 70s Friday. Uttech && .AVIATION...(For the 00Z TAFS through 00Z Sunday Evening) ISSUED AT 608 PM CDT Sat Apr 25 2020 VFR conditions will prevail overnight into Sunday as weak high builds into the area behind the storm system moving through the Ohio River Valley. Initial gusty northeast winds early this evening will become light and variable overnight into Sunday. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...Sheets SYNOPSIS...Gross SHORT TERM...Gross LONG TERM...Uttech AVIATION...Sheets
Area Forecast Discussion
National Weather Service Peachtree City GA
1055 PM EDT Sat Apr 25 2020 .UPDATE... Convection has moved out of the area with just high clouds streaming across. have made adjustments to hourly temperatures and dewpoints and dropped POPs through the overnight hours. Updated forecasts will be issued shortly. && .PREV DISCUSSION... /Issued 314 PM EDT Sat Apr 25 2020/ SHORT TERM /Tonight through Sunday Night/... Closed upper low continues to push through the Missouri Valley and into the Tennessee Valley at this hour. Although diffluence ahead of this system has created the lift for some light shower, instability has been the limiting factor thus far for more robust activity. CAPE has been largely on the order of 500 J/KG to 1000 J/KG thus far but RAP indicates within the next 6 hours a marked increase with in excess of 2000 J/KG by late this afternoon into the evening hours for far North GA. Will therefore not jump on any big changes to the forecast as activity should fill in nicely for aforementioned areas along with the threat for severe storms. Hail still the primary threat given cold mid levels but microbursts and to a lesser extent, tornadoes remain a possibility with this activity through this evening. Upper low to actually move north of the area tonight but appendage of vort max will bring additional lift to far north GA. Although instability will have subsided by then, still enough moisture and lift to warrant isolated to low end chance shower chances. Cooler behind this system and despite the cloud cover, still some lower to mid 40s expected for far NW GA. Clearing conditions for Sunday bu the drier and much windier conditions will pose their own issues. Likely that we will need a wind advisory and a Fire Danger Statement for conditions that develop by tomorrow afternoon. Will allow mid shift to refine and issue both of these. Deese LONG TERM /Monday through Saturday/... The long term period picks up on Monday morning with surface high pressure building across the local forecast area. With high pressure in place, expecting to have calm and dry weather on Monday with an increase in cloud cover for Tuesday ahead of the next low pressure system. By early Wednesday a mid-level trough is forecast to move into the area bringing southwesterly flow aloft and moisture to the area. The associated surface low is expected to be centered north of Georgia near the lower Great Lakes region on Wednesday before the low lifts to the northeast. Models have come into better agreement with this system although there are still some small discrepancies in low placement and strength. Regardless, a front is expected to move through the area on Wednesday with showers and thunderstorms possible. Rainfall totals for this system around around a quarter inch to an inch with the highest totals across northern Georgia and the higher elevations in the northeast. By late Wednesday, the GFS is showing the front clearing the area in the evening bringing some wrap around precipitation to far north Georgia. On the other hand, the ECMWF progresses more slowly, clearing the front on Thursday afternoon with wrap around precip across far north Georgia late Thursday into early Friday. Decided to go with a blend for pops in this period clearing the precipitation by Thursday afternoon. After this system passes, upper level and surface level ridge is expected to build into the area, keeping forecast relatively quiet through the end of the long term. Temperatures through the extended will generally be around average with highs generally in the 60s and 70s to lower 80s across the area, with low temps in the 40s and 50s. Reaves AVIATION.../Issued 729 PM EDT Sat Apr 25 2020/ 00Z Update... VFR conditions will persist through the TAF period. Winds will be southwest to west at 10-15kts with gusts 20 to 28kts throughout the entire period. //ATL Confidence...00Z Update... Medium to high all elements. Atwell && .PRELIMINARY POINT TEMPS/POPS... Athens 53 67 44 74 / 20 5 5 5 Atlanta 53 66 46 71 / 20 10 10 5 Blairsville 47 55 39 66 / 50 40 40 5 Cartersville 50 62 41 71 / 30 20 10 5 Columbus 54 74 48 76 / 5 0 5 5 Gainesville 53 61 45 71 / 40 10 10 5 Macon 54 74 46 76 / 5 0 5 5 Rome 50 62 42 71 / 30 20 10 5 Peachtree City 51 68 43 73 / 10 5 5 5 Vidalia 58 77 51 76 / 10 5 5 5 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Atwell LONG TERM....Reaves AVIATION...Atwell
Area Forecast Discussion
National Weather Service Grand Forks ND
937 PM CDT Sat Apr 25 2020 .UPDATE... Issued at 936 PM CDT Sat Apr 25 2020 Any lingering thunderstorms have weakened over our area, but light showers are still lingering over eastern ND and northwest MN. This activity is still expected to slowly spread east and then fall apart with main trough axis shifting east of our CWA. Mid level stratus is lingering though and if this doesn`t clear by morning could hold our overnight lows (especially in our east). Adjustments during this update focused on timing/coverage of lingering light showers, and held off on temps (clearing could still spread east by daybreak). UPDATE Issued at 659 PM CDT Sat Apr 25 2020 Mid level trough axis is still centered near our CWA, with the surface trough roughly along the REd River Valley. Where there is clearing there has been enough instability to still support a few weak thunderstorms, however overall trend has been weakening. Lighter showers may lingering later tonight in our east, but most locations should see a drying trends ahead of the next mid level shortwave/front Sunday afternoon. Adjustment made to reflect coverage/trends. Due to limited (and quickly decreasing) instability, isolated lighting and light rain will be only impacts this evening. && .SHORT TERM...(This evening through Sunday night) Issued at 335 PM CDT Sat Apr 25 2020 Main surface trof axis, now along a Lidgerwood to Finley to Niagaraline, will continue a slow eastward shift through the late afternoon and evening period... crossing the RRV corridor through the dinner hour and much of northwest Minnesota throughout the evening. Convection along and ahead of trof axis in southeast ND and adjacent portions of northwest through west-central MN continues to become more diffuse as the focus for mid level energy and surface heating have both shifted well south into eastern Sd and southwestern MN. However isolated thunderstorms are still possible, espousal in the southern RRV where early afternoon sunshine and surface heating was prevalent. The 19z RAP guidance maintains a fairly broad area of some 200-300 J/KG of 0-2 km CAPE alg and south of the Hwy 2 corridor through 02z, so convective elements in the overall pattern are likely to persist well into the evening. The 12z and 18z NAM runs have been overly wet and quite bullish, keeping a fair amount of precipitation across northwest MN during the overnight. However CAMs have steadily shown that convection should weaken considerably through early evening and essentially shutdown with nightfall, so have favored this drier soln. Sunday will see a second weak shortwave move into and across the area with scattered showers and isolated thunderstorms again possible through the afternoon and evening hours...though areas north of the I-94 corridor seem most probable at this point. Seasonably mild temperatures continue through Sunday into Monday morning... with highs from the upper 50s to the mid 60s, and lows in the 40s. .LONG TERM...(Monday through Saturday) Issued at 335 PM CDT Sat Apr 25 2020 Active weather coming up for the beginning of the extended period, with chances for showers and thunderstorms early Mon, and on Tue. A lull in the action should follow for mid week. Best chances for more impactful activity would appear to be on Tue. NW flow regime will see a shortwave moving through Sun night into Mon. On Tue a more substantial wave and area of sfc low pressure will be in play, along with more of a moisture feed. So with a decent boundary approaching and maybe 500 J/kg of CAPE available would expect a better chance for more sustained tstm activity during the day on Tue and maybe into the evening. marginally cooler temps will roll in behind the system Tue night into Wed. There are good indications that a decent ridge will start to build over the region for Thu and Fri moving temps trough the 60s and toward that 70 degree mark. Overnight lows mostly in the 40s, with 30s Tue and Wed night. Another chance for showers could come Fri, but plenty of variability exists this far out. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 659 PM CDT Sat Apr 25 2020 Besides lingering scattered showers minimal impacts to aviation during the evening period, with prevailing VFR conditions. There have been some easterly winds 10-15kt, but these should diminish and become light/variable tonight. Models show a period of stratus possibly reduce ceilings over northeast ND to MVFR (maybe even IFR) late tonight after 10Z which could impact KDVL or even as far east as KGFK. There should be drier air moving in, so I`m not confident in how low or widespread this would be. I induced mention at KDVL where there is more certainty, but held off of KGFK. This should lift 14-15Z if it occurs. Showers and isolated thunderstorms should develop into northeast ND as a front approaches late Sunday afternoon, with the best chances Sunday evening/Sunday night along/north of Highway 2. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. River point flood warnings continue across portions of the region. Refer to the latest flood warnings and statements for detailed information on specific locations. && $$ UPDATE...DJR SHORT TERM...Gust LONG TERM...WJB AVIATION...DJR
Area Forecast Discussion
National Weather Service Louisville KY
747 PM EDT Sat Apr 25 2020 ...Updated Aviation Discussion... .Forecast Update... Issued at 600 PM EDT Sat Apr 25 2020 Sfc low is just south of Evansville, with an occluding front arcing east and then SE, just west of Bowling Green but just north and east of Nashville. A fairly solid rain shield covers southern Indiana and much of central Kentucky, keeping a lid on SVR potential. There is a small dry slot near Lake Cumberland, and it will have a very limited opportunity to destabilize ahead of any convection along the occluded front. So we can`t rule out a strong storm or two down that way, but that window is closing and the more favorable environment for storms to rotate is solidly in TN per latest SPC mesoanalysis. Expect an update shortly to better convey the precip trends, which may involve carrying the categorical POP into the evening for more of the area. Over the next hour or so we expect to tone down our messaging as the severe threat diminishes. && .Short Term...(This evening through Sunday) Issued at 315 PM EDT Sat Apr 25 2020 18Z surface analysis reveals an area of low pressure near Mt. Vernon IL with a warm front extending southeastward through parts of western Kentucky. Just ahead of this low pressure system, convection has fired across west-central KY in the Pennyrile region. This area saw a bit of clearing and insolation earlier this afternoon which allowed temps to surge well into the upper 60s. Current mesoanalysis showed a bubble of instability from Hopkinsville northward to Owensboro where 750-900 J/Kg of CAPE was available and this area was coincident with moderately steep lapse rates of around 7-7.4 C/KM. The storms have been pulsing up and down producing up to 1 inch hail. Latest high resolution guidance suggests that this convection may organize into a short segment line and lift northeast, posing a threat of near severe hail, heavy rainfall, lightning, and gusty winds across Hancock, western Breckinridge, and Perry county IN over the next hour or so. Instability does wane a bit to the north and east of the current convection where earlier cloud cover has limited heating and near surface instability. Further south and east, mainly across the karst region, ongoing cloud cover and convective debris has thus far limited instability across the region. Convection has developed across west-central TN as expected and should continue to move northeastward this afternoon. While shear profiles remain favorable for severe convection, aforementioned concerns about instability results in lower certainty to severe potential. Latest HRRR guidance continues to show the potential for stronger storm development across southern KY this afternoon. Overall, thinking is that we`ll see widespread rain showers, with isolated to scattered stronger storms developing. Highest threat of severe weather still looks to remain south of a line from roughly Bowling Green over to Jackson and points south. Strongest storms would be capable of hail and damaging winds. However, shear profiles are strong enough that an isolated tornado can`t be ruled out. Convection should continue to move eastward and diminish in intensity this evening as the surface low moves through central Kentucky. Widespread rain showers will continue on the backside of the system this evening and will persist into the overnight hours. Lows tonight look to drop into the upper 40s. For Sunday, widespread cloudiness will continue with scattered to numerous rain showers continuing across the region. The shower activity looks to diminish in coverage by late afternoon, perhaps lingering into the evening in the east. Highs on the day will likely range from the lower 50s over across the Bluegrass region and the I-75 corridor, with middle middle 50s across the I-65 corridor. Some partial clearing could take place across the far west by afternoon which may allow temps to warm into the upper 50s. .Long Term...(Sunday night through Saturday) Issued at 245 PM EDT Sat Apr 25 2020 By Sunday evening the upper level trough axis will lie over the spine of the Appalachians with the surface low out east over the Garden State. Any remaining light rain should shut off around midnight in our eastern counties as wrap around moisture exits in the area. Low amplitude ridging aloft and associated surface high pressure will usher in drier air presenting the OH Valley with a pleasant Monday with morning temps in the high 30s. Could see a patchy fog scenario in the AM hours if clouds roll out early enough during the night to allow for sufficient radiational cooling. Otherwise, mostly sunny skies and light winds will see max temps rise into the mid 60s. By Tuesday a shortwave ejecting SE out of Canada will undergo lee- side cyclogenesis forming a closed low aloft and bringing showers and thunderstorms back to southern Indiana and central Kentucky from Tuesday through Thursday. Warm sector air ahead of the cold front and a modest LLJ will allow for a chance of showers through the day on Tuesday. Showers become more widespread Tuesday night and throughout the day Wednesday as the cold front sweeps through the region. Best chance of storms will likely be Wednesday afternoon into early evening with the aid of actual frontal lifting. The low center is progged to track across the Lower Great Lakes, which could place our area in a more favorable environment for potential severe weather, though dew points at this time are only expected to reach into the mid 50s with highs in the upper 60s. Will keep an eye on this system as newer data becomes available. By Wednesday evening, the vertically stacked low will begin moving east with wrap around moisture prolonging cloud cover and light rain chances through Thursday morning. Removed any mention of thunderstorms on Thursday as model soundings show a strong subsidence inversion at around 850mb capping any deep convective potential. Therefore, expect to see dry conditions for the latter half of Thursday with the exception of any pop up diurnal showers. Friday also looks to be dry as high pressure returns to the region. NW flow aloft will allow for subtle impulses to ride along the northern stream that could bring rain shower chances back to the area on Saturday. && .Aviation...(00Z TAF Issuance) Issued at 745 PM EDT Sat Apr 25 2020 Rain is currently being seen across much of the area and is expected to continue into Sunday as a surface low moves northeast along the Ohio River, with some breaks in the rain possible overnight. Ceilings are currently MVFR to VFR and look to lower into IFR range over the next few hours. IFR ceilings will then persist into tomorrow morning, eventually lifting from west to east during the day on Sunday as the rain pushes off to the east. Winds will start off out of the southeast and then shift to the west/northwest tonight as the low slides off to the east, with sustained wind speeds increasing to 10-15 kts. Wind gusts of 20-30 kts will be possible tonight and into tomorrow, eventually decreasing by Sunday evening. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update...RAS Short Term...MJ Long Term....CG Aviation...JML
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1052 PM EDT Sat Apr 25 2020 .SYNOPSIS... A warm front will push north through the region this evening. Another low pressure system will pass to the north late tonight pushing a weak cold front through tomorrow. A stronger cold front will cross the area Monday morning with high pressure building in behind it. A strong cold front will impact the region mid to late next week. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... As of 1000 PM Sat...Impressive shortwave trough continues to pivot into the TN/OH valleys this evening. The associated warm front is pushing northward slowly, currently settled around Cape Fear and spread NEwrd nearly paralleling our southern coast up to Cape Hatteras. This boundary is expected to push N over our CWA and priming the atmosphere for decent instability overnight. A dry line (well defined by Td gradient) will be approaching from the west but the best upper level support and omega will be displaced north and west towards the Triad. However, an upper level dry slot will be nosing into the region overnight depriving the region of deep moisture, though forecast soundings are beginning to show a weaker dry slot overnight and PWAT values over 1 inch, but uncertainty still remains regarding how much impact this will have on convective development. Latest 00Z hi res CAM runs hold onto a line of convection firing overnight, beginning shortly after 06Z. MLCAPE values across a variety of hi res models maintain a range of 1500-2500 J/kg with ample with mid- level lapse rates up to 7 C/km. With low LCL heights, up to 40 kt of 0-1km shear, 60+ kt of 0-6 km shear, and consistently curved hodographs, tornadoes continue to be a concern overnight. The 00Z HRRR shows SC values above 10 and STP values nearing 5 for much of the southern CWA. It is notable the 00Z HRRR also showed a decent line of discrete cells covering our southern coast and infiltrating as far inland as the coastal plains, essentially covering the entire CWA. While the greatest severe potential remains along the southern coast, it is worth emphasizing the entire CWA has a conditionally sufficient atmosphere conducive for severe weather. To reemphasize, this threat is highly conditional on a sufficient lifting mechanism being present and drier air aloft not depriving the environment of necessary moisture. If storms do fire, the highest threat window is between 06-12z overnight. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... As of 1000 PM Sat...No changes to prev disc. Prev disc...The boundary/front will sweep offshore pushing any potential convection well off the coast with dew points falling quickly during the day and skies clearing. Despite increasing CAA late as the upper low lifts north, low- level thicknesses remain high at around 1385-1390 m along with gusty southwesterly flow. Thus it should be another warm day with highs climbing into the upper 70s to potentially a few 80s closer to the coast. The atmosphere will be well mixed up to 850 mb with winds there of 30-40 kt, so some gusts to 20-25 kt are likely especially across the coastal plain. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... As of 315 AM Sat...Mainly dry conditions early next week before the next frontal system impacts the area Wednesday night through Thursday. Sunday night and Monday...The low will move off the Northeast coast Monday morning, bringing a stronger cold front Monday morning. While there is some modest pre- frontal moisture convergence, persistent dry air aloft is expected to win-out, making precip unlikely. Increased cloud cover associated with the frontal passage and better CAA behind this front will limit highs Monday to the mid- 60s to near 70. Tuesday through Wednesday...Ridging aloft builds overhead Tuesday and Tuesday night, keep a dry forecast in place. Surface high pressure passes south of the area during this time, settling offshore Wednesday as moisture advection begins to increase. Tuesday will be seasonable, with Wednesday a few degrees warmer. Wednesday Night through Friday...The next cold front, associated with stacked low pressure that will lift from the Midwest across the Northeast through the second half of the week, will impact the area Wednesday night and Thursday. Showers and thunderstorms are expected with this system, with strong low level wind shear thanks to a pre- frontal LLJ bringing the potential for organized convection. The severe weather threat will be refined in subsequent forecast updates. The cold front is expected to cross the area sometime Thursday into Thursday night, with high pressure builds back in Friday, bringing a return to settled weather. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... Short Term /through 00z Sunday/... As of 730 PM Sat...Stratus begins to break for the southern TAF sites as seen on satellite. Expect pred VFR conditions tonight for southern sites, but MVFR conditions for northern sites as lower decks look to linger through the overnight as a warm front moves north. Possible LLWS is suggested by models as the boundary moves north over the TAF sites after midnight, veering vertical wind profiles and forming a strong LLJ. Hi res models show a broken line of showers and tstms forming after 06z and pushing west to east over the TAF sites. Best storm coverage will likely be over the southern half of the region where the best instability is forecasted to develop. Cigs look to remain at MVFR for a few hours once the storms move through. VFR conditions will return after daybreak Sunday with gusty SW winds up to 20-25 kt. Long Term /Sunday night through Wednesday/... As of 320 AM Sat...VFR conditions prevail Sunday night. A cold front crossing the area Monday morning could bring some low cloud, but the potential for flight restrictions is uncertain. VFR returns later Monday and prevail through midweek. && .MARINE... Short Term /Tonight and Sunday/... As of 350 PM Sat...Latest local obs and buoys show seas have finally dropped to around 4-5 feet across the waters today in northeast to easterly flow of 10-15 kt. Winds will veer southerly overnight becoming southwesterly by daybreak Sunday as a warm front advances north across the waters. Winds increase back to 20-25 kt with gusts up to 30 kt, and seas respond in turn reaching a peak of 7-9 feet by late Sunday. New SCAs have been issued starting overnight and extending well into Monday as seas slowly subside. Long Term /Sunday night through Wednesday/... As of 330 AM Sat...Low pressure crossing the Mid-Atlantic will keep breezy southwesterly winds in place Sunday night. Elevated seas of 5-8+ ft in mainly southerly windswell will occur during this times, and SCAs will be need for most of the marine area. A cold front will cross the waters Monday, with a brief northwesterly surge behind it. Light winds then prevail Tuesday as high pressure passes south of the area, allowing seas to gradually subside, and bringing the best period for marine weather through the long term period. Southwesterly flow and windswell increases again Wednesday ahead of the next cold front. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...Beach Hazards Statement through Sunday evening for NCZ195-196- 199-204-205. MARINE...Small Craft Advisory from 11 AM Sunday to 4 AM EDT Monday for AMZ135. Small Craft Advisory from 2 AM Sunday to 8 PM EDT Monday for AMZ152-154. Small Craft Advisory from 2 AM Sunday to 2 PM EDT Monday for AMZ156-158. Small Craft Advisory from 11 AM Sunday to 2 PM EDT Monday for AMZ150. && $$ SYNOPSIS...MHX NEAR TERM...ML SHORT TERM...ML LONG TERM...RF/CB AVIATION...CB/ML MARINE...CB/MS