Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/28/23

National Weather Service Wakefield VA
943 PM EDT Thu Apr 27 2023 .SYNOPSIS... Low pressure approaches from the southwest this evening and tracks across the region late tonight into Friday. Another low pressure system will impact the region on Sunday. Cooler and drier conditions prevail early next week. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... As of 930 PM EDT Thursday... No major changes to the going forecast. Rain has spread into the southern Piedmont this evening and is expected to rapidly expand NE through the night due to strong isentropic lift associated with the 850mb warm front. Expect some locally heavier rainfall especially from central VA to the coast later tonight due to some enhanced frontogenetical forcing. This heavier rainfall will move northeast through the morning hours. In addition, a slight chance of thunder was added across NE NC late tonight as the latest HRRR shows about 200 j/kg MUCAPE in this area. Otherwise, just tweaked temperatures upward slightly tonight in line with latest guidance. As of 310 PM EDT Thursday... A stationary frontal boundary was situated near the NC OBX this afternoon. Meanwhile, an upper level wave was over the Ozarks with an attendant surface low over the central Gulf coast. High pressure (1025mb) was centered over southern New England. For our area, this resulted in some breaks in the clouds and mild temperatures for locations along and north of the VA Hwy 460 corridor and over on the Eastern Shore. Farther south, close to the coastal front, clouds were more plentiful (mostly cloudy to overcast) with some light rain noted along and just south of the VA/NC and points south. Through tonight, upper level low pressure tracks NE into the Ohio Valley with an associated shortwave trough/mid-level front lifting through Carolinas into the Mid-Atlantic by 12z Friday. Will have PoPs increasing from SW to NE overnight, starting with likely PoPs in the Piedmont by 03-06z and likely PoPs reaching the Eastern Shore prior to 12z Fri with categorical 80-100% PoPs west of the Ches Bay. The heaviest rain will remain confined to the Piedmont 0.50-1" through 12z Fri. Lows tonight ranging from the lower 50s NW to around 60F SE. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/... As of 340 PM EDT Thursday... A widespread, soaking rain is expected across the entire area Friday, especially during the morning and afternoon hours. This will be in association with a warm front that will be lifting N across the Carolinas overnight Thursday. The warm front will likely stall just S of the area for most of the day Friday. Rain will likely begin by ~4z across our SW counties and by ~12z across our NE counties (including the Lower MD Eastern Shore). Given favorable upper-level divergence and a nearly saturated atmospheric column, embedded areas of heavier rain are certainly possible. PoPs are 90- 100% for all areas before they start gradually decreasing into the evening as some top-down drying ensues. Depending on the degree of clearing, some sfc-based instability could develop across inland portions of southern VA and NE NC. Some of the CAMs depict this scenario, indicating there could be a few scattered tstms in the late aftn and evening hours. However, the exact details (coverage, timing, intensity) still remain quite uncertain. Due to this uncertainty, SPC has kept the marginal severe risk just to our S per earlier coordination. Rainfall totals Fri-Fri night are in the 1-2" range, with locally higher amounts possible across central VA. The HREF continues to indicate an elevated probability (30-50%) of an inch of rain in 3 hrs in these areas, especially NW of RIC. WPC maintains marginal ERO across the entire CWA. Could see some localized ponding of water on roadways and other similar minor All sites remain VFR early this evening, however expect conditions to deteriorate overnight as a warm front over the Carolinas moves north. This will allow rain to spread across the region from southwest to northeast overnight, along with lowering CIGS/VSBYS. Expect all sites to lower to IFR overnight into early Fri morning (RIC by 08z, PHF and ECG between 08z-10z, ORF by 11z and SBY between 12 and 15z). Expect IFR conditions through the day on Friday as well as steady rain, although it is possible that the rain will diminish some in the afternoon, especially at RIC and ECG. ECG may also see slightly improving conditions late in the forecast period if the warm front can move north. Expect gusty east winds on Friday, especially closer to the coast with gusts as high as 25kt. In addition, cannot completely rule out a thunderstorm at ECG Friday afternoon/early evening. Outlook...Although the rain is expected to diminish Friday night, expect IFR CIGs again Fri night as well as some fog inland due to plenty of low level moisture. Finally some improvement on Saturday before another low pressure moves into the area bringing more rain and deteriorating conditions. flooding in urban areas. Highs will be warmest closest to the warm front across southern VA and NE NC (in the upper 60s-low 70s). Elsewhere, it will generally stay in the low 60s. At the coast, onshore flow will also likely keep temps in the low 60s. Speaking of onshore flow, winds are likely to become breezy (out of E/ESE) in the late morning and early afternoon Friday adjacent to the Bay and ocean as the pressure gradient locally tightens INVOF the warm front. Lows Fri night 55-60. Saturday continues to look mainly dry outside of some lingering showers early in the day across the Northern Neck and areas to the NE. This is in response to developing SW flow with shortwave ridging just offshore. Some lingering low clouds will likely persist over our NE counties, keeping temps a little cooler there. A very isolated shower is also possible in the aftn but will keep PoPs in the silent range for now. Highs in the upper 70s to around 80 S with low-mid 70s across the N. The model guidance has come into better temporal agreement regarding the precip event for Sunday. However, there still remains quite a bit of uncertainty. In terms of the general synoptic pattern, a southern stream shortwave will induce sfc low formation across the Deep South late Saturday night with a widespread precip shield expected to move N/NE towards our area by midday Sunday. A cold front then crosses the area by Sunday night/early Monday morning. The exact track of the sfc low will determine high temps during the afternoon, including the potential for any instability development in the warm sector. For now, highs look to be in the upper 60s to mid 70s, highest S and SE. Also have categorical PoPs (80%) for most areas into evening, before precip diminishes for S to N and is offshore or NE of the area by Monday morning. In terms of QPF for Sunday, a widespread 0.5-1" looks likely, with higher amounts again possible. Given antecedent dry conditions, this rainfall (on top of Friday`s rain) will certainty be beneficial. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... As of 340 PM EDT Thursday... Cold front crosses the area Sunday night with a decent shot of CAA expected (especially across the W where dew points drop off quicker). Lows Sun night/Mon morning in the 40s W to 50s E. The winds turn W behind the front with some downsloping flow in the afternoon likely to keep highs on the milder side for Monday. Expect clearing behind the front with only a modest increase in high clouds by the afternoon. Highs in upper 60s to around 70. Overnight lows in the 40s (except in the lower 50s at the coast). The upper-level pattern through the middle of next week will be dominated by a large upper low N of the Great Lakes with below normal 500 mb heights over the eastern US. The upper low will gradually shift SE as a couple embedded shortwaves pass quickly through the area. This will likely keep persistent mid-high level clouds over our northern counties. Given dry lower and mid levels, expecting most dry conditions with little in the way of precip. Temperatures look to remain near to slightly below normal Tuesday and beyond, with highs in the 60s and 70s and lows in the 40s and 50s. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... All sites remain VFR early this evening, however expect conditions to deteriorate overnight as a warm front over the Carolinas moves north. This will allow rain to spread across the region from southwest to northeast overnight, along with lowering CIGS/VSBYS. Expect all sites to lower to IFR overnight into early Fri morning (RIC by 08z, PHF and ECG between 08z-10z, ORF by 11z and SBY between 12 and 15z). Expect IFR conditions through the day on Friday as well as steady rain, although it is possible that the rain will diminish some in the afternoon, especially at RIC and ECG. ECG may also see slightly improving conditions late in the forecast period if the warm front can move north. Expect gusty east winds on Friday, especially closer to the coast with gusts as high as 25kt. In addition, cannot completely rule out a thunderstorm at ECG Friday afternoon/early evening. Outlook...Although the rain is expected to diminish Friday night, expect IFR CIGs again Fri night as well as some fog inland due to plenty of low level moisture. Finally some improvement on Saturday before another low pressure moves into the area bringing more rain and deteriorating conditions. && .MARINE... As of 330 PM EDT Thursday... This afternoon, high pressure is located off the southern New England coast, ridging over local waters, while a stationary boundary is located over OBX. Winds are 5-10kt out of the SE. Seas are 2-3ft and waves are 1ft or less. Overnight and through tomorrow, an area of low pressure will form along a boundary well to the S and travel NE along the coast. Ahead of the low and the boundary, the pressure gradient will tighten and SE-ESE winds will increase. Winds will steadily increase overnight, reaching ~20kt sustained by Friday morning. By Friday afternoon, winds will be 25-30kt with gusts up to 40kt across the coastal waters north of Cape Charles light and in the middle/upper Bay. Elsewhere, winds will be ~20kt with gusts up to 30kt. Confidence of reaching gale thresholds in the northern coastal zones and middle/upper bay has increased due to high-res models and local wind probabilities trending toward stronger winds. Thus, have hoisted Gale Warnings for the coastal waters north of Cape Charles light and the Ches Bay north of New Point Comfort starting at 4am Friday morning. Elsewhere, SCAs are in effect, also starting at 4am. During this time, seas will build to 7-9ft across the north and 5-7ft across the south. Waves will be 3-5ft in the Bay and 2-3ft elsewhere. Winds will quickly diminish late Friday night to 10-15kt from south to north as the low pulls away. Winds look to remain sub-SCA through Saturday/Saturday night, but seas will likely remain at or above 5ft through the weekend. A frontal system will impact the region late in the weekend, bringing another opportunity for elevated winds. && .TIDES/COASTAL FLOODING... As of 620 AM EDT Thursday... Nuisance to minor coastal flooding will be possible from late Fri through Sat, mainly across the middle and upper portions of the Ches Bay and nrn coastal waters, due to strong ESE winds from a storm system eventually increasing water levels. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Gale Warning from 4 AM Friday to 1 AM EDT Saturday for ANZ630- 631-650-652-654. Small Craft Advisory from 4 AM Friday to 4 AM EDT Saturday for ANZ632-634. Small Craft Advisory from 4 AM to 10 PM EDT Friday for ANZ633- 635>638. Small Craft Advisory from 4 AM Friday to 7 AM EDT Saturday for ANZ656-658. && $$ SYNOPSIS...JDM NEAR TERM...JDM/MRD SHORT TERM...SW LONG TERM...SW AVIATION...MRD MARINE...AM TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1158 PM EDT Thu Apr 27 2023 .AVIATION... A surface ridge axis will persist over Southeast Michigan tonight resulting in quiet VFR conditions with an east wind trajectory. A shortwave will lift out ahead of a deep central NOAM upper level and impact Southeast Michigan beginning during the mid morning hours. Forcing will begin as very efficient isentropic lift before transitioning into organized deep deformation late Friday. Model soundings show low level saturation leading to LIFR conditions at the southern Taf sites after 14Z. Conditions are expected to be MVFR for a better part of the day at KFNT and KMBS. Compact pressure gradient tied to the low pressure system is expected to result in strengthening easterly Friday afternoon of 15 to 25 knots. DTW THRESHOLD PROBABILITIES... * High for ceiling at or below 5000 feet after 12z Friday. * Low for thunder Friday afternoon and evening. && .PREV DISCUSSION... Issued at 308 PM EDT Thu Apr 27 2023 DISCUSSION... A mid level wave over Montana will slide south to New Mexico by Friday, driving the low to mid level wave now over eastern Oklahoma northeastward across Se Mi. The 12Z model suite indicate this wave arriving as a quasi closed low-mid level circulation. Cloud cover will be on the increase through the night in advance of this system, which will limit nocturnal cooling potential thus inhibiting any frost/freeze concerns. A surge of high low-mid level theta e air (with 925mb dewpoints up to +10C) will be transported from northern Ohio into Se Mi between 09Z and 15Z Friday morning, marking the onset of rain across the forecast area. This will occur along the lead edge of the mid level deformation axis, which is expected to slowly traverse Se Mi during the day Friday and linger at least across the thumb and eastern portions of the area well into Friday evening. Model solutions all show a rather robust response within the mid level trowal axis. There is however some disagreement with respect to placement and persistence of this deformation. The NAM and RAP suggest a more prolonged region of forcing extending from Monroe up through Detroit to Port Huron; solutions which give the far eastern portions of the area much higher rain totals (over a half inch). The Canadian and ECMWF show a broader footprint in the ascent across the forecast area, although still have the strongest forcing across the far east. Based on recent trends in probabilistic guidance and the 12Z model suite, a longer duration of rain with higher rain totals will be warranted across the east, with pops and QPF tapering off toward the west. A series of mid level short wave features will move from central Canada into the upper Midwest/western Great Lakes by Saturday. Phasing of these features as well as the phasing of the northern stream jet with a jet streak over the srn Ohio Valley will lead to a rapid deepening of the northern stream trough and eventual development into a large deep upper low centered over the Great Lakes region by Sunday. There will be a period of subsidence and drying over Se Mi Sat morning into mid-late Saturday afternoon in the wake of the Friday system. This will also for some daytime recovery, supporting highs into the 60s. The lead edge of the mid level vorticity axis will then force a brief but strong period of ascent late Sat aftn/evng behind a surface cold front. This will result in a period of showers. Even with daytime recovery, model solutions suggest minimal instability along the front (a couple hundred J/kg CAPE ML cape at best), supporting just a chance of thunderstorms. The large upper low and associated mid level cold pool is forecast to linger over the Great Lakes region thru Wednesday. This will ensure cool and showery conditions for several days. The coolest airmass will be overhead Monday and Tuesday. While model soundings are suggestive of mainly rain showers, with 850mb temps forecast to dip down to -3 to -5C, can not rule out some wet snow mixed in at times. MARINE... Generally dry and calm marine conditions persist for the Great Lakes through the evening, aside from a band of rain showers that remains in tact over portions of Lake Huron. CONUS-wide perspective reveals a pair of low pressure systems tracking toward the Great Lakes, with the southern stream wave winning out and lifting extensive moisture and widespread rain overhead by mid morning Friday. During this timeframe winds back more easterly, with onshore flow elevating wave heights and gusts to Small Craft Advisory thresholds. Will hold off on headline issuance until the evening as there is still uncertainty as to the track of the low and duration of onshore flow. Winds and waves diminish through Saturday under overall stable conditions, although a rainy weekend is in store as a stalled upper low circulates overhead. HYDROLOGY... A compact upper low and associated surface low pressure will track across the region Friday and Friday night. This system will bring rain to most of the area. While most of the rain will be light, some intervals of moderate rain are possible. Total rainfall amounts are forecast to range from a tenth near Midland to six to seven tenths of an inch along a line from Detroit to Port Huron. The higher end of the probabilistic guidance (90th percentile) have these eastern locations receiving just over an inch. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...None. Lake Huron...Small Craft Advisory from 4 PM Friday to 4 AM EDT Saturday for LHZ421-422-441>443. Lake St Clair...Small Craft Advisory from 10 AM to 10 PM EDT Friday for LCZ460. Michigan waters of Lake Erie...Small Craft Advisory from 10 AM to 10 PM EDT Friday for LEZ444. && $$ AVIATION.....CB DISCUSSION...SC MARINE.......MV HYDROLOGY....SC You can obtain your latest National Weather Service forecasts online at
Area Forecast Discussion
National Weather Service Grand Forks ND
955 PM CDT Thu Apr 27 2023 .UPDATE... Issued at 953 PM CDT Thu Apr 27 2023 Significant update was done to greatly reduce rainfall in west central MN. Sfc low is in southeast SD and heavier rain area that may form overnight looks to be to our east/south. Thus anticipate just lighter rain areas overnight with HRRR, 02z NBM and 00z NAM guidance showing totals up to 0.10 inch Elbow Lake to Wadena, instead of the near 1 inch values from earlier. UPDATE Issued at 703 PM CDT Thu Apr 27 2023 Sfc low is in eastern South Dakota in the vicinity of Huron. It is moving ESE. Main 500 mb short wave is over western ND/NW SD and moving east. Main area of heavier rain showers and a few t-storms earlier is moving thru far south central ND and north central SD moving east. Also rain area in east central MN. Short term models indicate development of additional rain showers this evening in west central MN, but HRRR shows rain devlopment a bit farther south and looking at placement of sfc low I wonder if that will indeed be the case. && .SHORT TERM...(This evening through Friday night) Issued at 310 PM CDT Thu Apr 27 2023 Key Messages -Light rain will continue tonight into Friday morning -Winds may get a little breezy west of the Red River Valley tonight As of nearly 3 pm, the surface low had dropped into north central South Dakota. Temperatures had risen to the low 60s along the North and South Dakota border from south of Bismarck to the Wahpeton-Breckenridge area. The SPC meso page shows some weak SB and MLCAPE developing in this area and over toward Aberdeen SD. The latest regional radar shows a pretty steady area of light rain moving into the Grand Forks area right now. However, there is another area of showers/thunder around the northern edge of the surface low (around and south of Bismarck right now). Water vapor imagery shows some lightning activity out in this area. CAMs are showing possibly a further south track to this surface low, dropping any convection down into the Aberdeen area rather than our far southern FA late this afternoon/early evening. So doubting far southeast ND will see any thunder. However, think the trend this evening will be for the northern (highway 2) echoes to weaken as more activity develops along/south of the I-94 corridor. Wind speeds will also pick up as the low drops into SD, and this further southward track would mean less wind for this FA. Even so, winds may stay up tonight, just not be quite as gusty as earlier thought. The next round of light rain looks to arrive late Friday night. .LONG TERM...(Saturday through Thursday) Issued at 310 PM CDT Thu Apr 27 2023 Key Messages -The final round of light precipitation will continue through the day Saturday, before tapering off Saturday evening -A return to at least normal temperatures still appears likely by mid next week For Saturday into Saturday night, steep northwest flow will continue across the Northern Plains as another 500mb low drops into the Great Lakes. One more round of light precipitation that begins in the short term portion of the forecast Friday night, is expected to continue through the FA into possibly Saturday evening. This should not bring large rainfall totals either, with it currently appearing to be about a 10 percent chance for amounts greater than 0.25 inches. With the expected cloud cover and rain, temperatures will stay on the cooler side. Saturday through Sunday night also looks like a pretty windy period, with north winds. Rather than go with straight NBM guidance, blended in some CONSALL guidance to get slightly lower values. At this point, Saturday afternoon looks close to Wind Advisory criteria west of the Red River Valley. Wind gusts may drop off Saturday night, but sustained winds should not. Then, Sunday looks even windier, mainly within the Red River Valley. The current wind forecast would result in a Wind Advisory for portions of the area, with speeds slowly decreasing again Sunday evening. Once the precipitation and wind shift east of the FA, the question of a warming trend returns. Monday still looks like a cool day, with Tuesday showing more of an upward trend. Normal highs for late April are getting into the 60 degree range. Highs Wednesday and Thursday may actually rise to around 60 or slightly above. Not seeing any chances for precipitation throughout the Monday through Thursday time period. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 703 PM CDT Thu Apr 27 2023 Short term models once again I think are a bit too agressive with lowering ceilings over the area, esp NE ND where drier air is moving in from the north. So stuck with VFR ceilings tonight becoming MVFR overnight/Fri AM in NE ND/far NW MN. SE ND into WC MN VFR may have a better chance for MVFR cigs or isold IFR cigs overnight. Winds north-northeast, windier in SE ND/WC MN. && .HYDROLOGY... Issued at 310 PM CDT Thu Apr 27 2023 River flooding continues to diminish in the southern Red River Basin, and reach near crests in the northern Basin. Wahpeton has decreased below flood stage, and Fargo is on the way down. East Grand Forks already crested and is headed down. Areas toward Oslo have flattened out and will begin to fall over the next several days. Drayton and Pembina are still on the rise, with crests expected soon. Tributaries on the MN side continue to fall, with Hendrum the only remaining site in flooding. ND Tributaries are falling in the south, with Abercrombie and West Fargo currently in Minor. Harwood remains in Moderate, but is on the process of slowly diminishing. Areas rising are on the Pembina River, but are looking to remain just shy of minor flooding. Continued precipitation chances today, with up to a quarter of an inch possible. Further chances Friday evening into Saturday morning, with light amounts of precipitation. Dry and quiet conditions move into the region end of the weekend and into next week. Overland flooding continues along the Red River north of Grand Forks, affecting areas in Pembina and eastern Walsh county. This will slowly drop over time as water soaks into the ground and the Red River crests in the north. This will be the last hydro discussion for the Spring 2023 flood season. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...Riddle SHORT TERM...Godon LONG TERM...Godon AVIATION...Riddle HYDROLOGY...Spender
Area Forecast Discussion
National Weather Service Goodland KS
505 PM MDT Thu Apr 27 2023 .SHORT TERM...(This evening through Friday) Issued at 203 PM MDT Thu Apr 27 2023 This mid-afternoon water vapor loop and RAP analysis overlay revealed quite the impressive shortwave trough diving south within the broader longwave trough pattern. The mid tropospheric potential vorticity anomaly was centered across central Montana early in the afternoon with impressive downstream upward vertical motion ahead of the storm moving into eastern Wyoming and western Nebraska. This enhanced region of lift continued to draw closer to the tri-state region, and afternoon Day Cloud Phase Distinction RGB imagery showed a growing boundary layer cumulus field across northeastern Colorado into far northwest Kansas and adjacent far southwest Nebraska. The HRRR model seems to have a pretty good handle on this storm system, and there has been run-to-run continuity of surface-based shower and thunderstorm development across the northwest half of the the GLD CWA after 21Z. Boundary layer moisture was limited, however 500/700mb temperatures of -20/0C along with surface temperatures warming to the lower 70s resulted in deep layer, steep lapse rates and SBCAPE increasing to around 500 to 700 J/kg despite surface dewpoints in the mid to upper 30s degF. Thus, the greatest severe weather risk will be damaging straight line winds with the deepest convective plume late afternoon/early this evening. The threat of 60- 65 mph peak wind gusts has been messaged given this latest forecast thinking. As the strongest forcing for ascent moves across the tri- state region this evening, the HRRR suggests the leading axis of convection may form a loosely organized multi-cell line cluster as a modest cold pool develops. It will be difficult to differentiate an initial convective cold pool from the actual synoptic cold front itself, but there may be a bit of a separation between the two meteorological features. Regardless, the synoptic cold front will be pushing south quickly later on tonight. By that time, the axis of greatest lift and subsequent numerous showers will push south of our region down into southeastern Colorado and southwestern Kansas. North-northwest winds behind the synoptic cold front will likely be 25 to 35 mph sustained with gusts well in excess of 40 mph at times...through at least the first half of the day Friday as northwest Kansas and surrounding region remains in the fairly tight MSLP gradient as the upper level cyclone continues to move south-southeast down into New Mexico and the Texas Panhandle. Back to the precipitation forecast, the official forecast will reflect a precipitation type changeover to a wet snow before ending over the higher elevation areas of the GLD forecast area (western/southwestern half, particularly in vicinity of the Palmer Divide), but any snow before ending will likely be fleeting with essentially no accumulation expected. .LONG TERM...(Friday night through Thursday) Issued at 203 PM MDT Thu Apr 27 2023 Over the weekend, the northwest flow pattern on the longwave scale will continue across much of the western Great Plains and adjacent Rockies as a deep gyre becomes established across the Great Lakes region. Another deep trough will develop along the West Coast early next week with another deep upper low likely to develop out of the trough out west. The hemispheric scale regime looks quite blocky with the tri-state region in between these large gyres with very little in the way of sensible weather to affect the region. This will likely result in fairly light winds for the most part and temperatures quite seasonable with the warmest air mass shunted well to the south through at least Tuesday. The latest models suggest the Great Lakes region and West Coast gyres dissolving with more westerly momentum crossing the Rockies mid to late next week. Mid next week and beyond, the forecast becomes far more uncertain in terms of temperature forecasting and (severe?) convection. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 505 PM MDT Thu Apr 27 2023 For KGLD, VFR skies through 05z Friday along with a chance for a VCTS. After 05z, a drop to MVFR ceilings along with 6sm in light rain showers. Winds northwest 15-30kts. Periodic gusts 40-50kts are also possible. For KMCK, VFR skies with light rain and VCTS through 06z Friday, then VFR/MVFR ceilings, with light showers through 11z. Winds northwest 10-20kts. Gusts to 40kts after 06z Friday. LLWS 00z-01z Friday 300@55kts. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...WFO DDC/Umscheid LONG TERM...WFO DDC/Umscheid AVIATION...JN
Area Forecast Discussion
National Weather Service Gray ME
1112 PM EDT Thu Apr 27 2023 .SYNOPSIS... Our unsettled weather pattern of late will take a short break on Friday into Saturday as high pressure builds over the region. This will result in clearing skies and seasonably mild temperatures. The high will move northeast of the area on Saturday allowing our next area of low pressure to arrive late in the day. Showers arrive Saturday afternoon over western areas and in the evening over eastern areas. The showers will become a steady rain late Sunday afternoon into Monday. Expect more rain showers through much of next week. && .NEAR TERM /THROUGH FRIDAY/... 11pm Update...Fog is just now being reported at some observation sites and have increased some of the coverage along the coast and interior ME. A similar trend may be needed for southern NH tonight as guidance still indicates greater probability of vis restrictions and lower clouds tonight. Otherwise, calm winds and clear skies have allowed temps to rapidly decrease. Went with 10th percentile NBM temps and MOS guidance for remaining temp trend. 7pm Update...Shower activity will continue to decrease into the evening hours with a final line of light rain passing over the coastal region. Updating rain chances and some temps this evening were the primary changes, but will be keeping tabs on any fog development overnight. This may occur first where MRMS showed accumulation over the past 12 hrs (from Rockport, ME west through much of the northern half of NH and into western ME). 425 PM Update... Convective showers have over performed and drifted towards the Mid Coast of Maine. Have increased PoPs along the coastal plain over the next couple of hours to account for these trends. Previously... Latest RAP analysis shows that a few hundred J/kg of SB CAPE has developed with filtered sunshine today. This has allowed for convective showers to blossom within a surface trough draped along the NH/ME border. Low freezing levels and steep mid level lapse rates will continue to make graupel or pea sized hail possible as there have already been reports of pea sized hail with convective showers earlier today. Shower activity wanes with the setting sun this evening followed by skies turning mostly clear overnight. The recent wet weather in addition to areas that receive rainfall today will aid in the formation of radiational fog tonight as skies turn mostly clear. Have followed the previous forecast package logic with patchy fog along the coastal plain and across northern valleys with areas of fog in sheltered locations across the interior. Lows tonight will drop into the 30s areawide with favorable radiational cooling spots dipping below the freezing mark. && .SHORT TERM /FRIDAY NIGHT/... Surface high pressure over eastern Canada lurches into the Gulf of Maine Friday while a narrow ridge axis builds over the forecast area Friday afternoon. This will bring fair weather with mostly sunny skies to start followed by increasing high level clouds from SW to NE Friday afternoon. Highs on Friday will climb into the 60s across much of the area while high pressure moving into the Gulf of Maine will bring winds onshore and thus cooler conditions along the coast. Onshore flow will continue into Friday night with hi res guidance bringing in marine stratus/fog into the coast late Friday evening and spreading inland Friday night. All the while, an area of low pressure to the southwest of New England will continue to spread high and mid level clouds over the area. Lows Friday night will range from the upper 30s to low 40s. && .LONG TERM /SATURDAY THROUGH THURSDAY/... We head back into an active weather pattern for much of the long term forecast as a large upper level low forms over the western Great Lakes late Saturday and slowly drifts east, reaching eastern New England mid next week. This will result in a prolonged period of unsettled weather. In the dallies, on Saturday High pressure retreats to the northeast over the Canadian Maritimes. Surface low pressure underneath the previously discussed upper level low over the western Great Lakes moves slowly east. Another area of low pressure develops along the Gulf of Mexico Coast. Moisture in the form of clouds and showers will move northeast during the day on Saturday, expect most of the shower threat to hold off until late in the day/evening and primarily over NH. How quickly the showers move further east is a question as there are signs that the departing high may hold ridging over Maine Saturday night into Sunday thereby slowing the eastward progress of the showers. On Sunday the two lows will start to consolidate into one low just west of the Delmarva Peninsula by late in the day. This will result in the showers trying to push further east Sunday afternoon...again how quickly this happens is still uncertain. The low will move to the North Sunday night and weaken somewhat as it gets captured underneath the upper level low. A period steady rain likely arrive Sunday night into Monday. As the low gets absorbed underneath the upper level low on Monday expect the steady rain to taper to showers. Tuesday through Thursday...we will be underneath the upper level low. This will result in showers though the period. There is a possibility of another steadier round of rain Tuesday Night into Wednesday as the upper level lows energy passes directly overhead with a surface low underneath the upper level low crossing the area. Rainfall amounts may be enough to result in minor flood issues over area rivers and streams Sunday Night and Monday. Temperatures will be below normal Saturday and Sunday. If the rain tapers off quick enough on Monday/Tuesday we may briefly approach normal temperatures. As the upper low passes over head temperatures will return to below normal values for the remainder of the extended forecast period. Models: The 00z global models when compared to the 12z NAM were quicker in developing the steady steady rain on Sunday Afternoon. The NAM holds the steady rain off until Sunday Night and has ridging from the departing high holding on longer thus keeping drier air in place for much of the weekend. Will need to see if this trend continues in future model runs. 12z GFS is slightly slower than the 00z GFS with regard to the onset of the steady rain but is faster than the NAM. For now will lean toward the global models...but will be a little slower with the onset time of the precipitation. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... Short Term...Patchy fog will develop tonight with the highest confidence in flight restrictions at KCON, KAUG, and KLEB. VFR prevails Friday with increasing high clouds late Friday. Onshore flow could push marine stratus/fog into the coastal plain Friday night and this could bring flight restrictions to coastal terminals at KAUG. Long Term...MVFR conditions Saturday with areas of IFR Saturday Night as showers & drizzle and fog develop. IFR with areas of LIFR possible Sunday Afternoon into Monday in rain...drizzle and fog. Some improvement likely to develop during Monday as steady rain tapers to showers. && .MARINE... Short Term...Winds and seas remain below SCA thresholds tonight through Friday night. Patchy fog could develop over the waters tonight and there is a signal for more widespread fog over the waters Friday night as onshore flow strengthens. Long Term...Wind and waves below SCA Saturday....building to SCA levels Sunday and continuing on Monday as low pressure moving west of the region increase winds and waves. Winds may approach gale force Sunday Night into Monday Morning. Winds subside to below SCA levels on Tuesday however waves will remain at SCA levels. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Cornwell/Schroeter SHORT TERM...Schroeter LONG TERM...Lulofs
Area Forecast Discussion
National Weather Service Indianapolis IN
935 PM EDT Thu Apr 27 2023 .Forecast Update... Issued at 933 PM EDT Thu Apr 27 2023 - Light Rain passing overnight - Cloudy and becoming cooler Surface analysis late this evening low pressure centered over the Arkansas/Mississippi boarder. A warm front extended northeast across Western KY to SE Indiana. Cool and dry easterly flow was in place across Central Indiana. Radar shows an area of showers ahead of this from pushing northeast into Central Indiana. However, dry dew points within the lower levels, in the lower 30s, were hindering precipitation reaching the ground. This should be overcome in the next few hours. Overnight, the low pressure system is expected to push northeast to Central Indiana amid the SW flow aloft as shown within the water vapor imagery. This should allow the precip to advance across Central Indiana through the overnight hours. HRRR suggests this precip shield should exit the area near 12Z and forecast soundings at that time show some dry air arriving aloft. Thus will focus highest pops from south to north over the next 6-8 hours, trending toward low pops then. Given the expected clouds and rain, lows in the lower 50s and upper 40s appear the mark. && .Short Term...(This evening through Friday) Issued at 301 PM EDT Thu Apr 27 2023 Tonight. During the overnight hours tonight a broad upper level low pressure system will track across Missouri into the Ohio Valley with periods of rain expected. Strong isentropic lift arrives starting at 00Z with the lowest pressure condensation deficits around 03Z in the southern counties. This lines up well with the expectations for the heaviest precipitation being between 00Z and 06Z. Model soundings show little to no instability along with near moist adiabatic lapse rates as soon as the atmosphere moistens. As the surface low then moves into southwestern Indiana closer to daybreak a TROWAL then develops to the northwest of the surface low from Terre Haute to Kokomo with weak lift allowing rain to continue into the daytime hours. The influx of moisture will also help moderate temperatures through the overnight hours with lows around 50. Friday. The surface low will continue to slowly move into western Ohio into the morning hours. The forcing aloft associated with the TROWAL will weaken and then end by noon as drier air works in behind the low. Winds will then shift from the northwest to west by the evening. The northwest winds through much of the day will keep temperatures cool again with highs only reaching into the upper 50s to low 60s. The residual moisture will keep skies mostly cloudy through much of the day with clearing arriving late in the day. && .Long Term...(Friday night through Thursday) Issued at 301 PM EDT Thu Apr 27 2023 * Damp and unsettled pattern through the long term * Cool temperatures late weekend through the middle of next week Guidance continues to advertise a blocky pattern developing as time goes on, broadly characterized by deep and anomalous closed lows over the Great Lakes into the northeastern CONUS and along the West Coast, with a narrow, high-amplitude ridge in between roughly over the Rockies throughout much of the long term period. This will lead to fairly damp, cool, and raw weather through much of the long term, particularly for the latter half of the weekend into mid week next week, although temperature recovery toward the end of the period will not be particularly robust, and the 8-14 day outlook remains below normal across the area. This will obviously stand in stark contrast to the very pleasant warm period experienced earlier this month. Friday evening looks primarily dry and cool as surface low pressure pivots northeast into the Great Lakes and the column rapidly dries from above. Cannot entirely rule out some lingering drizzle in the evening, but the low level moisture shallows out fairly quickly, so this would be minimal. Through the weekend into early next week, the upper level low will steadily consolidate and deepen, with impulses pivoting around the larger low along with one or more accompanying secondary cold fronts providing additional forcing for precipitation. Shower chances will be in the forecast continuously from Saturday through Tuesday for at least portions of the area, peaking diurnally in the afternoons when the very modest available instability will be maximized. Low thunder chances will be necessary on Saturday, mainly in the afternoon and evening, per convective indices, but the remainder of the time looks to be simply showers. Temperature-wise, the long term will begin with temperatures slightly below normal, although this will quickly change as sub-zero 850 mb temperatures make their way into the area late in the weekend into early next, resulting in temperatures, max temps in particular, as much as 10-15 degrees below normal. Diurnal ranges will be limited many nights by cloud cover, which should minimize frost threat, but will have to keep this in mind should any clearing materialize. && .Aviation...(00Z TAF Issuance) Issued at 630 PM EDT Thu Apr 27 2023 Impacts: - VFR deteriorating to MVFR tonight and then IFR on Friday. - Winds shift from east to northwest through the period. Discussion: An upper level low pressure system over MO will push across Central Indiana through the period. Associated rain showers over southern IL and western KY along with their MVFR conditions are expected to advect across the TAF sites overnight, before departing the area after 09Z-12Z. Surface winds will shift from the east to the north as the low passes, eventually becoming NW by Friday afternoon. Forecast soundings show best saturation and moisture this evening. but deep moisture is lost in the wake of the low, leaving just lower level saturation. Thus after the best forcing departs tonight, just lingering IFR Cigs are expected for much of Friday. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ Update...Puma Short Term...White Long Term...Nield Aviation...Puma
National Weather Service Jackson KY
1110 PM EDT Thu Apr 27 2023 .UPDATE... Issued at 1110 PM EDT THU APR 27 2023 The initial batch of showers are breaking up a bit, but some will still be around through the night with thunder still a possibility, as well. Have updated the forecast mainly to fine tune the PoPs and Wx through the rest of the night per radar and CAMs trends. Did also include the latest obs and trends for the T/Td grids. These updates have been sent to the NDFD and web servers along with a forthcoming freshening of the zones and SAFs. UPDATE Issued at 735 PM EDT THU APR 27 2023 23Z sfc analysis shows low pressure approaching the area from the southwest and this has pushed a warm front north into eastern Kentucky and along with it a large area of showers. These are affecting all but the far northwest and southwest parts of the area with steady, mainly light, rain under mostly cloudy conditions. The rain is affecting the temperatures through the area, as well, with readings in the mid 50s amid the showers to the lower 60s in the north just ahead of the steadier returns. Meanwhile, amid east to southeast winds of 5 to 10 mph, dewpoints are generally in the low to mid 50s with some patchy fog around with the showers at times. The current forecast is right on track so have mainly added in the latest obs and trends for the T/Td grids along with incorporating the CAMs trends into the PoPs and Wx grids. These updates have been sent to the NDFD and web servers. && .SHORT TERM...(This evening through Friday night) Issued at 443 PM EDT THU APR 27 2023 Late this afternoon, a shortwave trough was approaching the mid MS Valley while an upper level low was centered over Ontario. A general area of troughing extended from Ontario to the Northern Plains/Upper MS Valley and then southeast toward LA. An additional upstream shortwave was dropping southeast across the Northern Plains and Northern Rockies regions. At the surface, an area of low pressure was tracking across AR and also nearing the MS Valley region with an initial warm front lifting north across eastern KY at this time and currently bisects the CWA with dewpoints in the 40s to the north and dewpoints mainly in the 50s to the south. Areas of showers were lifting north from eastern TN into eastern KY as of late afternoon with rain having reached the ground as far north as a PBX to JKL line. Thus far, rainfall across the southwest has been under a tenth of an inch. Tonight, the shortwave trough currently nearing the mid MS Valley into the Lower OH Valley and approach the Great Lakes tonight while an the shortwave currently over the Northern Plains and Northern Rockies is expected to dig south to the Central Rockies and Plains. The initial shortwave trough will track into the Great Lakes on Friday while a trough continues to develop in the Central Conus. The shortwave in the Great Lakes is expected to lift further north on Friday night and begin to merge with the Central Conus trough while the digging shortwave trough will continue southeast to the Southern Plains and likely begin to close off as it moves toward the Ozarks to eastern TX regions. At the sfc, the area of low pressure nearing the MS Valley region at this time is expected to track northeast into the Lower OH Valley tonight and pass northwest of eastern KY on Friday. The trailing frontal zone will near eastern KY late tonight and cross the are on Friday to Friday evening. Increasing moisture with PW expected to rise from current 0.7 inch to 1.2 inch range at present to in excess of 1 inch for all the area for a period of time this evening into the overnight before PW decreases overnight as the axis of the shortwave lifts to near the OH River. The combination of this increase in moisture along with lift from the passing shortwave will lead to periods of showers and perhaps a thunderstorm this evening and tonight, though chances for showers will diminish from southwest to northeast by the overnight hours as the shortwave passes and moisture begins to decrease. Any thunderstorms that manage to develop could produce briefly heavy rain and might lead to locally heavy rain and an isolated high water issue or two in poor drainage areas. However, relatively dry antecedent conditions lead to this potential being low. Even the worst case 6 hour QPF max from the 12Z HREF has generally no more than 1.5 to 2.5 inches as a worse case scenario which again due to the antecedent conditions would likely cause very few if any issues. PW near an inch is expected to linger on Friday as the area of low pressure passes to the northwest and the frontal zone moves east. RAP and other model guidance suggests MLCAPE of around 1000 J/kg and MUCAPE perhaps in excess of 1500 J/kg around 19Z in the eastern counties while effective shear in the 30 to 35KT range is expected. This could result in a couple of stronger storms and with low level lapse rates forecast to exceed 7C/km gusty winds will be a possibility though the CAPE shear balance suggests a few rotating updrafts or supercell structures will be possible. Some small hail can not be ruled out as well along. This potential has been added to the HWO. Chances for showers and thunderstorms will diminish on Friday evening into Friday night behind the departing area of low pressure and boundary. .LONG TERM...(Saturday through Thursday) Issued at 405 PM EDT THU APR 27 2023 Key Points: * The period begins with a breif lull in precipitation as the area is caught in between systems. Rain chances increase late Saturday and into Saturday night as a cold front approaches the area. * Temps start out near normal for the weekend before dropping off to well below normal for the remainder of the period as CAA remains in place in the low levels. The long term period starts out with an amplified upper level pattern across the CONUS. A pair of troughs will cover a portion of the CONUS, one near the Midwest and into Canada and another southern stream trough located across the southern Plains. Across the west, an upper level ridge will be centered across southern California and will extend into southwestern Canada. Progressing forward in time, the southern stream trough will move east/northeast through the Southeast and Mid Atlantic regions into early next week. The larger, northern stream trough will slowly shift eastward while reinforcing disturbances deepen an upper level low over the UP of MI and Lake Superior with an ~524 dam low located over the region by mid Monday. Models depict this trough slowly churning across the upper Great Lakes and slowly toward the lower Great Lakes Tuesday night before finally getting some pep in its step and moving toward the Northeast by the end of the period. As for sensible weather, the period will start out in a relative precipitation lull as a disturbance exists the area to the northeast and the next disturbances sit to the southwest and the northwest of the area. Precipitation chances will increase late Saturday into Saturday night with showers and storms possible. A cold front will sweep through the area on Sunday and will begin to usher CAA into the area along northwest flow. PoPs will also taper off into Sunday evening as the atmosphere dries. Additional rain chances will come Monday and Tuesday afternoon, with mainly diurnally driven showers across the northern and eastern counties. Some gusty winds will be possible Monday afternoon in a post frontal environment which will be clear and will support decent mixing. Saturday will be the warmest day of the period with low to mid 70s expected. Sunday will be slightly cooler as precip and clouds increase over the area,highs will top out in the mid to upper 60s. Highs Monday through Wednesday will be on the chilly side with upper 50s to low 60s expected as CAA remains in place at 850mb. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) ISSUED AT 800 PM EDT THU APR 27 2023 Mainly VFR conditions were reported across eastern Kentucky at issuance time. However clouds will continue to lower from southwest to northeast as the warm front lifts deeper into eastern Kentucky with its large area of showers. A thunderstorm cannot be ruled tonight, though the best chances would be west of I-75. The rain will further moisten the lower levels and MVFR, with even some IFR in the higher elevations, should develop across the southwest parts of the area, including SME and LOZ before 04Z. Then, as showers and a few thunderstorms lift north and east with the warm front, MVFR conditions and even some times of IFR are anticipated for most of the 04 to 12Z period. A general improvement in ceilings from mainly IFR and MVFR into the MVFR range and even some VFR in the southeast can be expected later in the day, Friday. Winds will begin the period from the east to southeast at less than 10 kts before becoming more southerly at 10 kts or less from 04 and 12Z as the low pressure area tracks into the Ohio Valley. Winds are expected to then become southwest at 10 kts or less for most of the day, Friday. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...JP LONG TERM...BATZ AVIATION...JP/GREIF
Area Forecast Discussion
National Weather Service Melbourne FL
1013 PM EDT Thu Apr 27 2023 ...New UPDATE, MARINE, AVIATION... .UPDATE... Issued at 1011 PM EDT Thu Apr 27 2023 Current...Another very active weather day, with ongoing strong to severe activity still impacting east central FL. Current radar has two main areas of thunderstorms; the initial cluster of activity that began in the early afternoon hours has maintained intensity as it moves offshore, with additional strong storms developing in the wake of an already worked over environment. A secondary line of storms has rapidly moved onshore from the Gulf of Mexico this evening and is now approaching Daytona Beach to the Orlando metro, with a history of wind gusts just below severe criteria. Over the next few hours, severe thunderstorms at the immediate coast will drift offshore, however the threat for frequent lightning, gusty winds, heavy rain and brief tornadoes is still ongoing from Cape Canaveral southward to Jupiter Inlet from this isolated single cell convection. To the west, the broad multi-cellular line is abruptly moving east at around 45 mph, although the threat for severe weather is quickly diminishing. Latest HRRR erodes this secondary line prior to it reaching the Atlantic coast, but based on the environment supporting continued convection even after earlier storms, am not to keen on this solution. The good news is that any areas that may have missed out on rain this afternoon will likely see the opportunity for at least a few hundredths prior to sunrise. All severe weather hazards were observed today, with numerous reports of funnel clouds (no confirmed tornado touchdowns), quarter sized hail, wind gusts of 60 mph, and torrential downpours leading to minor flooding of roadways. Friday-Friday Night...Most of Friday morning is forecast to remain dry, though considerable cloud cover will be present. The temperature forecast may need further adjustment in future forecasts, but for now, 60s and low 70s is how we expect to start the morning. Persistent SSW flow and WAA will send deep moisture northward across the peninsula. As weak mid level ridging pulls east, mid level energy will provide support for more showers and storms to develop over the east-central Gulf. This activity will spread across central and southern Florida from late morning through mid afternoon. Additional storms with greater severe potential may form on the nose of this convection, notably south of the Space Coast and along the Treasure Coast. A Marginal Risk for severe storms is outlined by the Storm Prediction Center for all of east central Florida on Friday. Conditions gradually improve Friday evening with only light to moderate showers remaining and temperatures falling through the 70s. && .MARINE... Issued at 1011 PM EDT Thu Apr 27 2023 Tonight-Friday Night...Seas building this evening into tonight from 3-4 ft up to 5 ft, mainly offshore from Sebastian Inlet northward. Seas return to 3-4 ft, 5 ft well offshore on Friday. A moderate SSE breeze continues this evening, decreasing some nearshore tonight, while veering SSW after midnight. SW winds 12-17 kt Friday. Rounds of showers and lightning storms will continue over the local waters into tonight, and once again Friday afternoon. Some storms will be capable of producing wind gusts greater than 35 knots, large hail, frequent cloud-to- water lightning, and locally higher waves. && .AVIATION... (00Z TAFS) Issued at 1011 PM EDT Thu Apr 27 2023 Isolated to scattered convection from KMLB southward will move offshore through 04Z with a secondary, broad line of strong thunderstorms just on the edge of KDAB to KISM. MVFR/IFR cigs and vis will impact nearly all terminals as this line moves to the east/southeast through 06Z, gradually lifting initially at KLEE. Winds gusts over 35 knots are likely especially for interior terminals, with the line losing forcing as it reaches coastal terminals south of KTIX. A brief lull in shower and storm activity will last from 08Z-14Z before another early start to convection arrives over the interior tomorrow morning. && .PRELIMINARY POINT TEMPS/POPS... DAB 83 67 83 67 / 70 70 70 20 MCO 88 70 84 71 / 80 60 60 30 MLB 85 69 86 69 / 70 70 70 20 VRB 86 69 88 69 / 50 60 70 20 LEE 89 69 83 70 / 70 70 60 30 SFB 87 69 84 69 / 80 60 70 20 ORL 89 70 84 71 / 80 60 60 30 FPR 84 69 88 69 / 40 60 70 20 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && $$ Smith/Tollefsen/Haley/Sedlock