Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/17/20

Area Forecast Discussion
National Weather Service Bismarck ND
918 PM CDT Tue Jun 16 2020 .UPDATE... Issued at 917 PM CDT Tue Jun 16 2020 Forgot to remove the Wind advisory...this corrects that. UPDATE Issued at 910 PM CDT Tue Jun 16 2020 Thunderstorms continue to try and break through the CAP this evening, but so far none have been successful. As the cold front in western North Dakota moves a little more east this evening we should see more convection, as a single storm or several clusters of storms,from just west of Bismarck north into central North Dakota. In the meantime, we will cancel teh wind advisory as winds have diminished below advisory criteria. UPDATE Issued at 756 PM CDT Tue Jun 16 2020 We will cancel the wind advisory for south central North Dakota, and keep the advisory for the James River Valley going until 10 pm. UPDATE Issued at 612 PM CDT Tue Jun 16 2020 Current radars show convective initiation over northeast Bowman county, at least one cell at this time. This is very close to the HRR timing and location, so we have some confidence the HRR CAM model is probably on track. Current forecast looks good. && .SHORT TERM...(This evening through Wednesday) Issued at 332 PM CDT Tue Jun 16 2020 Severe thunderstorm potential late this afternoon through tonight west and central, and late Wednesday afternoon and evening across the James River valley, is the focus of the short term forecast. As of 20 UTC, surface pressure falls on the order of 2-3 mb/3 hrs are centered on northwest and north central ND with related mass- field responses of thermal and moisture advection ongoing. RAP- based objective analyses show strong MLCIN at this hour, which is consistent with the warm elevated mixed layer sampled by the 12 UTC RAOBs. Forecast soundings from multiple model cores including the 12 UTC CAMs suggest weakening MLCIN by late afternoon as low- level theta-e advection continues, though residual capping still remains in most profiles, casting uncertainty on the probability of surface-based convective initiation through early evening. It does, however, appear that the window of opportunity for surface- based convection will be focused in west central ND roughly along and ~75 miles east of the Highway 22 corridor, northward to about Stanley and across the western end of Lake Sakakawea. It`s along that corridor where a low-level wind shift is forecast to reach by 00 UTC. The length of the wind shift will have a non-zero risk of convective initiation. However, two mesoscale areas of focus could be around the western end of Lake Sakakawea, where the low- level thermal ridge axis may overlap the moist axis closer to a surface low in northwest and north central ND, and around the Dickinson area where low-level warm air advection may be most focused the next few hours. The CAPE-shear setting through early evening for any surface-based parcels will be characterized by MLCAPE on the order of 2000 J/kg, effective shear magnitudes of 40-50 kt, and very steep low- and midlevel lapse rates. Given at least a modest orthogonal component of deep-layer wind fields to the surface wind shift, and the large amount of capping present, discrete modes -- and supercells -- are favored. This setting favors the possibility of very large hail up to baseball size along with damaging gusts, though again this is a very conditional risk. CAMs through the 19 UTC HRRR are relatively consistent in this scenario though, with modest probabilities and clustering of UH >150 m2/s2 from the 12 UTC HREF centered on west central ND. Low-level hodographs enlarge with time toward sunset, but the relatively modest boundary layer moisture with dewpoints generally in the 60 F range will contribute to MLLCL heights close to 2000 m AGL, which will constrain the tornado risk. Otherwise, from late evening through about 09 UTC, convection will likely increase in coverage toward a scattered nature as heights aloft fall more steadily as an upper-level trough shifts eastward. Forecast soundings support related cooling of the warm elevated mixed layer, while a strong low-level wind maximum on the order of 50-60 kt as low as 2000 ft AGL continues moisture transport along and ahead of an eastward-shifting cool frontal boundary. This may allow for clusters of elevated strong to severe convection, when and where moisture profiles are deep enough for elevated parcels to have reduced MUCIN while MUCAPE remains in the 2000-3000 J/kg range. Given the elevated nature of the effective inflow layers after dark in this setting, as supported by forecast soundings, hodographs will become shorter and thus effective shear overnight will decrease closer to 40 kt. As a result, we are messaging hail up to golf ball size with overnight storms along with a continued risk of damaging gusts. On Wednesday, the surface front will shift eastward and may again result in surface-based convective initiation in the James River valley by late day. However, there is spread among 12 UTC models with how far east the front will be by the time initiation occurs, and deep-layer shear vectors will be oriented parallel to the front. Thus, messy convective modes are expected, which may limit the ceiling of the severe risk, but large CAPE will be present to compensate to some extent. Finally, the Wind Advisory through this evening is on target, with forecast soundings in the Ashley, Oakes, and Jamestown areas all supporting peak winds at the top of the mixed layer in the 45 to 50 kt range from 21 to 00 UTC, suggesting near high wind criteria south winds. We`ve increased messaging in the advisory for gusts to 55 mph, though confidence in more than isolated gusts nearing warning criteria within the low-level warm air advection regime was too low to upgrade any counties to a warning. .LONG TERM...(Wednesday night through Tuesday) Issued at 332 PM CDT Tue Jun 16 2020 Cooler, but seasonable temperatures and periodic shower and storm chances will highlight the long term, including the weekend. The consensus of the 00 through 12 UTC global deterministic and ensemble suites calls for a middle- and upper-level low to evolve over south central Canada by Thursday as the initial trough aloft lifts northeastward. The middle- and upper-level low is forecast to only slowly shift eastward through in the succeeding days, with cyclonic flow and lower heights on its southern flank in place in the northern Plains. Some spread exists in the 850 mb temperatures forecast by individual GEFS members, but the coldest air is likely to arrive late this week with NBM-driven forecast highs only in the 60s in the west and north Thursday, and forecast lows Thursday night in the 40s in most areas. Confidence in temperature trends is above average through the weekend -- with forecast highs mainly in the 70s F, but with a slow warming trend -- given a relatively small one standard deviation in NBM membership forecasts. We have a chance of showers and thunderstorms in the forecast many times and places, but it won`t be a washout; predictability of impulses embedded in the flow is low, and activity will likely be diurnally driven. By early next week, it appears midlevel heights will begin to rise, leading to a drying and warming trend, though the exact timing of that transition is somewhat uncertain. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 612 PM CDT Tue Jun 16 2020 VFR expected through the forecast. Hazards to aviation include scattered thunderstorms over west and central North Dakota this evening. Also low level wind shear will develop over the James River Valley when strong southerly low level winds develop between 1 to 2 thousand agl across this area after midnight, and surface winds diminish at KJMS. Otherwise, initial thunderstorm development will be across KDIK by 01-02z spreading north and east to KMOT-KBIS between 03 and 06z. Storms expected to diminish in intensity after 06z-08z. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA SHORT TERM...CJS LONG TERM...CJS AVIATION...WAA
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
633 PM CDT Tue Jun 16 2020 .SYNOPSIS... Issued at 312 PM CDT Tue Jun 16 2020 A high amplitude H5 pattern continues across the CONUS today. Low pressure was noted over South Carolina with a trough extending south into southern Florida. West of this feature, a positive tilted ridge of high pressure extended from Texas, north northeast into the upper Mississippi valley and the western Great Lakes. West of this feature, closed low pressure was located over western Washington state. A trough of low pressure extended south of this feature into northern California and northern Nevada. Downstream of this trough, a strong shortwave was noted from eastern Idaho into southwestern Montana. HT. falls of 60 to 90 meters were noted from northeastern Nevada, to southern Idaho and northern Utah this morning. At the surface, low pressure was located over far southeastern Montana. A warm front extended east northeast from the low into northeastern North Dakota, while a cold front extended to the southwest into west central Wyoming. A surface trough extended south from the low from eastern Wyoming into eastern Colorado. Winds were southerly this afternoon and were gusting up to 48 MPH at North Platte at 2 PM CT. Temperatures at 2 PM CT ranged from 88 at Ainsworth to 96 at North Platte and Imperial. && .SHORT TERM...(This evening through Wednesday night) Issued at 312 PM CDT Tue Jun 16 2020 Temperatures and a small threat for thunderstorms tonight, then temperatures and the threat for thunderstorms Wednesday afternoon and Wednesday night are the main forecast challenges. For tonight, the latest NAM12 and GFS solns indicate a rather strong low level jet tonight with speeds ranging from 50 to 60 KTS generally east of the Panhandle. A nice surface pressure gradient sets up tonight with a deepening surface trough of low pressure noted over the western Panhandle. That being said, for locations east of the panhandle, lows tonight will be very mild with readings in the upper 60s to around 70. In the eastern panhandle where winds will be lighter, lows will be in the lower to middle 60s. As for the thunderstorm threat this evening, it will be confined to the far western forecast area. The latest NAM 12 solution indicates a weakening in the cap across northeastern Colorado and the southern Nebraska Panhandle later this afternoon. This could be enough for initiation in these areas. Steering winds will carry this activity to the north northeast into the evening hours. With only 15 to 20 KTS of deep layer shear available, not expecting much in the way of severe storms across the western forecast area this evening. Storms however, will be high based and may produce some gusty winds given the current strong surface winds. A cold front will approach the northwestern forecast area Wednesday morning, stalling across the panhandle for the remainder of the day. Temps in advance of this feature will surge well into the 90s once again, with some readings possible around 100 in the far southwestern forecast area. The latest NAM12 soln develops a dryline bulge which noses into Keith, Arthur and McPherson counties around 21z Wednesday. This would be a favored area for storm initiation late Wednesday afternoon given a weakening cap as depicted in the NAM12 soln as well as the 12z HRRR which develops convection around 22z Weds to the northwest of North Platte. Any activity which does develop in west central Nebraska, will quickly track north northeasterly given the H5 steering winds. As this activity lifts north, it will encounter CAPES of 2500 to 4000 J/KG in north central Nebraska Wednesday evening. Deep layer shear will increase into the evening hours as well with 30 to 40 KTS of deep layer shear noted. This will favor strong to severe storms with the main threat being strong winds (inverted V type soundings) and some marginally large hail given the decent mid level lapse rates. By late evening, the front will begin to progress east across the forecast area with a more generalized threat for showers and thunderstorms overnight. ATTM, the highest pops will be over northern and northeastern portions of the forecast area, where mid level support is strongest. .LONG TERM...(Thursday through Tuesday) Issued at 312 PM CDT Tue Jun 16 2020 The before mentioned front, will push into eastern Nebraska Thursday morning taking with it the primary threat for thunderstorms. For the bulk of the forecast area, cooler and dry conditions are expected with highs mainly in the mid to upper 70s. By Friday, the front will lift north into southern and southwestern Nebraska. At the same time a decent mid level disturbance will lift across the area Friday night. This appears to be the best chance for precipitation across the forecast area over the next 7 days. A second northern stream trough of low pressure may bring some showers to the forecast area Saturday night into Sunday, but forecast confidence is low as there are some decent differences between the EC and GFS solns. Beyond Sunday forecast confidence slips further as the GFS has an active northern stream across the northern CONUS while this pattern is depicted over southern Canada in the latest EC soln. The latter would favor warmer temps and ridging across the western CONUS. With the latter solution favored, highs will rebound back into the upper 80s to lower 90s early next week. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 633 PM CDT Tue Jun 16 2020 VFR is expected across western and north central Nebraska tonight and Wednesday. Isolated thunderstorms are possible west of highway 61 this evening and again Wednesday afternoon 21z-00z affecting the Sandhills and northern Nebraska. LLWS tonight is expected to produce occasional SFC G40-45KT through 09z Wednesday morning. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Buttler SHORT TERM...Buttler LONG TERM...Buttler AVIATION...CDC
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1044 PM EDT Tue Jun 16 2020 .SYNOPSIS... Low pressure will cross the area tonight, weakening inland Wednesday into Thursday. High pressure builds back into the area later this week into the weekend. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... As of 10 PM Tues...Surface low pressure east of Cape Fear continues to very slowly move northward, with deep moisture advection continuing across eastern North Carolina. scattered to widespread showers continue late this evening, with areas of heaviest rainfall focused along the coast where an inverted trough axis and greater instability offshore is providing for more convective elements and higher rainfall rates. Primary changes to the forecast for the late evening update were to more aggressively bring drying in from the southwest as mid-to- upper level subsidence begins to move in in the wake of the low aloft. Flash Flood Watch remains in effect for all CWA counties along and east of US Hwy 17. An additional 1 to 3 inches of rainfall are locally possible, especially along the Crystal Coast and Outer Banks. Previous Discussion...Hi-res guidance shows pockets of heavy showers enveloping eastern NC into the evening. SPC mesoanalysis shows a wide area of strong deep moisture convergence along our southern counties south into Onslow Bay. RAP analysis also shows a broad area of 35-45 kts of 0-6km bulk shear across the CWA overlapped by an area of 500-1500 J/kg of CAPE west of Hwy 17. As a result, storms are expected to continue developing over Onslow Bay and the Gulf Stream and move NNE ashore. With marginal severe parameters in place, any strong to severe storms that form offshore could maintain strength moving inland. The possibility for waterspouts continues with the risk of a few moving ashore. The bulk of the heavy rain and thunderstorms will begin lifting north over the northern OBX and NE counties as the upper low lifts NW towards central NC with the sfc low following suit. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... As of 415 PM Tuesday...Upper-level low crawls across central NC during the day on Wednesday with low-level flow turning southerly. A bulk of the precip will stay towards our northern tier into VA, but scattered showers and storms will be possible during the day. Latest HRRR guidance shows MLCAPE values around 1500-2000 J/kg during the day, providing ample fuel for storms. Hi-res guidance disagrees on storm coverage, but overall, expect scattered showers and thunderstorms through Wednesday. Daytime heating will be more efficient tomorrow with partly sunny skies across the SE portions of the CWA, which may promote convective activity. Along with Srly flow, we can expect high temps to move closer to 80. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... As of 255 PM Tue...Unsettled weather will continue across Eastern NC through late week. Lingering stationary front along with a stacked low will continue to produce scattered to numerous mainly diurnal showers and thunderstorms through Friday. We should finally begin to dry out some over the weekend into early next week, with a return to warm and humid conditions. Wednesday night through Thursday...Low continues to become vertically stacked across the Carolinas, slowly weakening and lifting northward Wed night and Thu. Rainfall should taper off Wed night and Thu will still have the potential to be locally heavy but coverage should be less, as the upper/surface lows begin to weaken and lift north. The precipitation then becomes more tied to diurnal cycle. Friday through Tuesday...The upper low weakens late in the week, however upper troughing will continue along the eastern seaboard which will continue to allow for a decent coverage of showers and thunderstorms, especially inland during peak heating when instability is maximized. The upper trough axis slowly shifts eastward through the period and coverage of storms expected to gradually diminish each day. Temps will also be on a warming trend with above normal temps returning by the weekend with highs potentially in the lower 90s inland locations Sunday. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... Short Term /Through Wednesday/... As of 730 PM Tuesday...Low pressure off Cape Fear will lift across the area tonight into Tuesday, bringing deep moisture convection and widespread flight restrictions. IFR will generally prevail through the morning, though brief improvement is possible, depending on how precip coverage trends. Then, by mid to late morning, ceilings will begin to improve, first to MVFR, then potentially VFR by afternoon. Visibility restrictions will be limited to those resulting from pockets to rainfall, which could be heavy, brining IFR visibilities at times, especially this evening and overnight. Long Term /Wednesday Night through Sunday/... As of 150 PM Tuesday...Sub-VFR conditions possible into Thursday, with scattered to scattered showers and tstms. Conditions then expected to improve to VFR by Thurs night. Coverage of storms expected diminish late in the week as the upper low lifts north of the area, however an upper trough will remain over the area with shower and thunderstorm chances continuing, especially during peak heating each afternoon. && .MARINE... Short Term /through Wednesday/... As of 8 PM Tuesday...Gusty northeast winds funneling down the mouth of the Neuse River necessitates the addition of the Neuse to the SCAs. Previous Discussion...Small Craft Advisories remain in effect for most area waterways as low pressure lifting toward the area have NE winds 20-30 kt persisting. Seas will be 4-6 ft for the southern waters with 5-7 ft waves in the central and northern waters through the night. Winds will begin to subside tomorrow morning and gradually shift SE during the day. Expect 4-6 ft waves along the central and northern waters calming to 3-5 ft by Wed night. Long Term /Wednesday night through Sunday/... As of 255 PM Tue...An weak area of low pressure will lift north of the region Wednesday night into Thursday, then the waters will be under the influence of Atlantic high pressure and a lee trough with decent boating conditions expected during this period. The flow will mainly be S/SW 5-15 kt through Sunday with the strongest winds in the afternoons and evenings with seas 2-4 ft, highest during the periods of stronger flow. && .CLIMATE... Record rainfall amounts for 6/16 (Tuesday) LOCATION RAINFALL/YEAR New Bern 2.51/2010 (KEWN ASOS) Cape Hatteras 2.46/1893 (KHSE ASOS) Morehead City 3.55/1965 (COOP - Not KMRH ASOS) && .MHX WATCHES/WARNINGS/ADVISORIES... NC...Flash Flood Watch until 10 AM EDT Wednesday for NCZ045>047-080- 081-092-094-193>196-198-199-203>205. Beach Hazards Statement through Wednesday evening for NCZ196- 203>205. MARINE...Small Craft Advisory until 6 AM EDT Wednesday for AMZ131-135- 137-230-231. Small Craft Advisory until 8 PM EDT Wednesday for AMZ150-152- 154. Small Craft Advisory until 11 AM EDT Wednesday for AMZ156-158. && $$ SYNOPSIS...MHX NEAR TERM...ML SHORT TERM...CB/ML LONG TERM...JME/CQD AVIATION...DAG/CB MARINE...JME/CB/ML CLIMATE...MHX
Area Forecast Discussion
National Weather Service New York NY
855 PM EDT Tue Jun 16 2020 .SYNOPSIS... High pressure over New England remains in control through Wednesday and then gradually shifts offshore Wednesday night into Friday. A cutoff low drifts north into the forecast area over the weekend. A frontal system approaching from the west merges with the low early next week. && .NEAR TERM /THROUGH WEDNESDAY/... Minor adjustments to the forecast to account for latest observations and trends. High pressure will continue to be in control bringing tranquil conditions to the Tri-State through Wednesday. The upper level low across the southeast will only make slow progress northwestward with ridging in place aloft over the region. The ridging should keep most clouds away from the area, but there may be just a scattering of high clouds at times tonight, especially near the coast. Will also have to watch for some low cloud development across far SE CT and eastern Long Island. Dry air and ridging should hold much if any low clouds offshore. The NAM profiles seem most aggressive, but even the HRRR and RAP hint that some low clouds could develop briefly around day break. Overall, mostly clear to partly cloudy conditions tonight with lows ranging from the low 50s inland to the middle and upper 50s most elsewhere. The core of the high begins to shift towards the coast on Wednesday, but otherwise similar conditions are anticipated as observed in previous days. Some high clouds are likely with fair weather flat cumulus possible in the afternoon. Sea breezes are likely which will keep temperatures in the middle and upper 70s, but locations furthest inland may be able to reach 80 degrees as the onshore flow will take longest to reach those locations. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/... The high begins moving offshore Wednesday night with ridging aloft remaining in place across New England. With the high moving offshore, low level moisture begins to increase. There is greater potential for a deck of low stratus to develop Wednesday night, especially near the coast. Low clouds should diminish Thursday morning with daytime heating leading to another partly cloudy day on Thursday. The high pressure will continue shifting offshore with surface ridging across the region remaining in place. The upper level low will only slowly lift north- northwestward. Any moisture and lift associated with the upper low is likely to remain well to our south and west, so have continued with a dry forecast for Thursday. High temperatures will be closer to seasonable averages in the upper 70s to low 80s. Immediate shoreline locations will see temperatures in the lower to middle 70s. There is a moderate rip current risk on Wednesday at the Atlantic facing beaches due to a continued 3 to 4 ft easterly swell. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Upper level cut off low drifts north Thursday evening into Friday bringing with it remnants of subtropical moisture. For the majority of the day Friday the additional moisture is only visible through an increase in cloudiness. However by the late afternoon and into the evening we could see a few showers and isolated thunderstorms develop. These showers become more likely over northeastern New Jersey and the Lower Hudson Valley. Areas not impacted by showers should reach the low 80s. Diurnal afternoon showers are expected over the weekend owing to the moist airmass overhead. Precipitable water values around 1.75 inches coupled with some elevated instability should be sufficient for late afternoon convection. There is a fairly sharp west to east gradient of CAPE with the highest values over northeast New Jersey and the Lower Hudson valley. Meaning that thunderstorms should be confined to those areas and a passing shower over the NYC metro can`t be ruled out. Temperatures should be slightly warmer over the weekend with afternoon highs in the mid 80s and overnight lows in the mid to upper 60s. Monday into the early part of next week a longwave trough over the Great Lakes will have to be monitored. Models are depicting an embedded shortwave north of Lake Ontario shifting into Quebec through the day. As this happens the associated front boundary shifts moisture eastward over southern New York. It is possible that the lift from the shortwave and the boundary will initiate more storms late Monday. Then Tuesday the main longwave trough axis moves into central New York which again should promote showers and isolated thunderstorms Tuesday evening. There is a moderate rip current risk on Thursday at the Atlantic facing beaches due to gradually subsiding easterly swell. The rip risk may decrease in the afternoon. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... High pressure will remain anchored across the northeast through the middle of the week. VFR through the period, although there is low chance for MVFR/IFR stratus formation late tonight into early Wednesday morning for KGON/KISP. E/SE early this evening will once again back around to the E/NE overnight at 5 kt or less. A familiar but weaker wind flow on Wed, with E/NE winds 5-10 kt in the morning, becoming ESE/SE in the afternoon. .OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY... .Wed Night-Thu...MVFR/IFR cigs possible for coastal terminals late Wed Night into Thu morning, likely for eastern terminals. E winds AM, S/SE winds PM. .Thu Night-Sun...MVFR/IFR conds possible at night/early morning. Chance of aft/eve shower or thunderstorm on Fri-Sun for NYC/NJ and western terminals. S winds. && .MARINE... High pressure will remain in control over the waters through Friday leading to a weak pressure gradient and Sub-SCA conditions. South winds dominate over the weekend ranging 10-15 kts over the ocean waters with gusts less than 20kts. Wave highs hover around 3 feet over the ocean waters and 1 foot over the Long Island sound. Winds become southwesterly Monday into Tuesday and increase slightly 13-18kts over the ocean as a frontal system approaches from the west. && .HYDROLOGY... No hydrologic impacts are forecast through this week. && .EQUIPMENT... NYC NOAA Weather Radio Station KWO35 (162.55 MHz) is undergoing its final stages of testing, and is operating at full power. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ UPDATE...DW
Area Forecast Discussion
National Weather Service Blacksburg VA
718 PM EDT Tue Jun 16 2020 .SYNOPSIS... The region was between low pressure off the North Carolina coast and high pressure over New England. Little change in this weather pattern is expected through Thursday so the wet and unseasonably cool weather will persist. Over the weekend a cold front coming out of the central United States will cross the Great Lakes and bring a chance of showers and thunderstorms to the Mid Atlantic area. && .NEAR TERM /THROUGH WEDNESDAY/... As of 700 PM EDT Tuesday... No significant change in the forecast rationale and details. The slow-moving upper low and surface wedge maintains an impressive blanket of clouds and scattered rainfall across the region this evening. No hydrologic impacts to this point with few more details discussed in hydro section below. Previous valid discussion... As of 155 PM EDT Tuesday... Closed upper low drifts back north to the Virginia/North Carolina border tonight and Wednesday. This will prolong the very deep flow off the Atlantic. 3km NAM was showing to areas of enhanced low level convergence tracking across southern Virginia and northern North Carolina this afternoon and evening. Also little change in the weather pattern expected at the surface with a low along the North Carolina coast and high pressure wedges down the central and southern Appalachians. While there will be some upslope tonight and Wednesday, the wind direction was mainly east to northeast so not expecting a big enhancement in rainfall amounts along and into the foothills. Expect the air mass to become unstable under the core of the upper low and over the Virginia and North Carolina piedmont by Wednesday afternoon. Cloud cover may limit heating but temperatures aloft will still be cool and provide larger lapse rates. Will keep probability of precipitation high tonight and Wednesday with favorable synoptic and isentropic lift and good inflow of high axis of precipitable water. Have added a chance of thunder Wednesday afternoon around the periphery of the wedge. Combination of persistence and NBM used for lows tonight. Expect highs on Wednesday to be a couple of degrees warmer than today. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... As of 200 PM EDT Tuesday... The ever-present cutoff low remains the dominant feature through this period, keeping us in anomalously cool, wet conditions. The closed low continues its slow retrograde from the Carolinas towards the OH Valley. Widespread light rain will persist during this process, even as the low rejoins the northern stream late on Friday and begins to open up. The center of the low will rotate our flow from easterly to southwesterly and some instability will be introduced into the atmosphere, bringing some chance for storms Thursday and Friday PM. This period will see our region undergo a slight warm up, getting closer to normal values (but still below), with highs in the 60s and 70s. && .LONG TERM /SATURDAY THROUGH TUESDAY/... As of 200 PM EDT Tuesday... The cutoff low will become a shortwave and be swept off towards New England over the weekend. Some ridging over us should clear the skies a bit and let some peeks of sunshine through, helping warm us back to normal temperatures for mid-June. Persistent rain coverage will be replaced by afternoon convection, especially along the mountains. By Monday, areal coverage of precipitation will expand again, as the next upper trough approaches bringing showers and storms to the region. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... As of 720 PM EDT Tuesday... Flight categories across the forecast area currently range from VFR to IFR at observing sites this evening but a general deterioration in CIGs is expected overnight. VSBYs will fluctuate with passing showers of variable intensity, but predominantly 3-5SM expected. KDAN may see the most intense rainfall later this evening with some lower CIGs/VSBys if the stronger convective activity over the NC coastal areas maintains coherence and remains on track. A TEMPO group will cover that possibility. Winds are generally east to northeast under 10 kts with occasional higher gusts and this also will be slow to change during the entire valid TAF period. Extended Aviation Discussion... The closed upper low will continue to meander about the central and southern Appalachians through Friday, finally beginning to lift to the north by the weekend. As the low weakens, the threat for prevailing IFR conditions and persistent -RA will begin to decrease. Showers and thunderstorms, with MVFR ceilings and visibilities are expected Saturday and Sunday, mainly each afternoon and evening. && .HYDROLOGY... As of 715 PM EDT Tuesday... Rainfall amounts are really sort of all over the map to this point (23Z/7PM), with storm totals ranging from less than 0.25 inches over parts of the southside and the far western basins to pockets of 3+ inches in several areas. Hard to even discern a generalized pattern but 1 to 2 inches are fairly widespread per radar and ran gages, with slight underestimation by radar compared to gages. With another 1 to 2 inches of rain forecast (QPF) and isolated higher (and lower) amounts there may still be some hydrologic issues but they will be limited in scope and magnitude unless some sustained higher rain rates can move across a basin. No RFC river forecast points are currently forecast to reach Flood stage, though a few are progged to hit Action stage but it will depend on how this variable QPF works out. Of note, the National Water Model (NWM) experimental products based HRRR short-range (0-18 hr) and GFS ensemble QPFs (18-hr to 10-days) are showing low probabilities for bankfull stages to be reached in any of the Blacksburg WFO rivers and streams. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS NEAR TERM...AMS/PC SHORT TERM...VFJ LONG TERM...VFJ AVIATION...AMS/PC HYDROLOGY...PC