Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/25/20

Area Forecast Discussion
National Weather Service Bismarck ND
954 PM CDT Fri Jul 24 2020 .UPDATE... Issued at 948 PM CDT Fri Jul 24 2020 We have cancelled all counties of the watch except for Dickey, Lamoure and Stutsman. Strongest storms are currently over Dickey county into Brown and McPherson counties in South Dakota. UPDATE Issued at 915 PM CDT Fri Jul 24 2020 Quick update mainly for pops/wx. Severe convection is now limited to the James River Valley. UPDATE Issued at 751 PM CDT Fri Jul 24 2020 Clusters of convection continue over the James River Valley. Clusters are embedded in stratiform precipitation and it looks like the threat for severe convection for the most part, should continue to diminish through the remainder of the evening. However an isolated severe gust or marginally severe hail can not be ruled out. UPDATE Issued at 451 PM CDT Fri Jul 24 2020 Quick update for ongoing shower activity over southwest into northeast ND. Additional thunderstorms are expected to develop around Bismarck eastward toward Carrington probably between 6 and 7 PM this evening, and move east. Updated pops based on latest MRMS QPE and blended some time lagged HRRR/ESRL HRRR through the evening. && .SHORT TERM...(Today through Saturday night) Issued at 215 PM CDT Fri Jul 24 2020 Forecast highlights in the short term period will be warm and humid weather through Saturday, and strong to severe thunderstorm chances this afternoon/evening and again Saturday afternoon/evening. Currently, upper level ridge axis across the Western Great Lakes region with upper level low pressure spinning over southwestern Canada. This puts strong southwest flow aloft across the Dakotas. Weak sfc boundary from south to north across central South Dakota into south central North Dakota. Warm and very humid along to east of this boundary, especially across eastern North Dakota where current heat index values range from 95 to 105F degrees. Heat headlines across the James River Valley remain valid with this forecast issuance. Upper level jet streak along with subtle mid level embedded waves have contributed to mid level clouds and a few areas of showers and isolated thunderstorms at times the past several hours across western and central areas of the state. Precipitation has been minimal with cloud bases over 10K ft AGL. A stronger embedded wave now over eastern Wyoming will track northeast into western South Dakota this afternoon, then across south central and eastern North Dakota this evening. This feature will trigger strong to severe convection initially later this afternoon across western South Dakota, then along the boundary into south central and eastern North Dakota this evening after 23Z. MLCAPE values in the 3000 to 5000 J/kg range will be plenty for severe storms along with marginal deep layer shear of 30-35 KTs. Storm hazards will initially be large hail to around ping pong ball size given the shear, though shear vectors parallel to the sfc boundary says any discrete convection will be short lived. Storms will then eventually morph into a wind threat later in the evening as storms congeal to more linear. An additional threat will be heavy rainfall rates with the high instability and precipitable water in the 1.5-2 inch range. For Saturday, not much has changed from earlier discussion. Sfc boundary reestablishes over western North Dakota in the morning, then shifts east during the day as the upper low now over southwestern Canada ejects east across far southern Canada near the International Border Sat afternoon/evening. Thunderstorms will develop during the afternoon along this sfc boundary, where there still looks to be better 0-6km bulk shear and instability linkage along the front. Shear vectors now look more parallel to this boundary, so perhaps more multicellular development vs. discrete. Makes sense that SPC has kept us in the marginal risk on Saturday and did not go with a slight risk outlook given the above. The heat index may be a concern again in southeast North Dakota Saturday afternoon ahead of the front, however there remains uncertainty on what the boundary layer moisture will be following tonight`s expected storms and rainfall. .LONG TERM...(Sunday through Friday) Issued at 215 PM CDT Fri Jul 24 2020 Cooler, dry, and much less humid on Sunday as surface high pressure builds across the Dakotas. Maybe a few showers and/or thunderstorms across the north during peak heating as the upper low will be across central Ontario and a northwest flow may bring enough mid level energy for development. Sfc high remains over the region into Monday resulting in another dry day with some return flow southwest warming temperatures there. Upper level ridge moves into our area Tuesday, then to our east Wednesday/Wed night when we see a return of shower and thunderstorm chances, though models not exactly in agreement. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 948 PM CDT Fri Jul 24 2020 Thunderstorms are expected over the James River Valley through 04-05Z. Low stratus and fog possible from KBIS to KJMS early Saturday morning, but uncertainty to high at this time to include in either TAF at this time. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...TWH SHORT TERM...NH LONG TERM...NH AVIATION...TWH
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
647 PM CDT Fri Jul 24 2020 ...00z Aviation Update... .DISCUSSION...Updated for latest aviation discussion below. && .AVIATION...A very complicated and low confidence forecast over the next 24 hours, with amendments likely to the TAFs periodically as Tropical Storm Hanna approaches the lower Texas coast. The main hazards in this TAF period are heavy rainfall, reducing visibilities and ceilings, and very strong winds, including low- level wind shear occurring over a few airports. VFR conditions will prevail this evening, with light easterly winds transitioning to southerly winds later this evening. Winds will gradually turn westerly/northwesterly overnight tonight and increase through the day on Saturday. By late morning, west/northwest winds will become very gusty, gusting between 30-40+ knots through Saturday afternoon, with off/on heavy rain and occasional rumbles of thunder. Included low-level wind shear for MFE and HRL for wind speeds/gusts between 40-50 knots at 2000 feet above ground level. Although there is still lots of uncertainty with timing and duration of the heavy rain/winds, forecast confidence is very high that hazardous flying conditions will occur starting overnight tonight and will continue to deteriorate through the day tomorrow. Overall forecast confidence: low && .PREV DISCUSSION... /issued 440 PM CDT Fri Jul 24 2020/ ..TROPICAL STORM HANNA THREATENS DEEP SOUTH TEXAS WITH DANGEROUS FLOODING... SHORT TERM (Now through Sunday Night): GOES-16 visible satellite imagery continues to show better development of Tropical Storm Hanna as it continues to move west-northwest across the northwest Gulf. Deep convection continues to develop around its center. Latest position from the NHC, as of 1 PM CDT, has the center of TS Hanna located at 27.3N and 93.7W, moving west-northwest at 9 mph. KBRO radar has been fairly quiet over land today, with most of the shower and thunderstorm activity remaining offshore and on the immediate coastline. Consistent runs of the HRRR have shown isolated to scattered showers and thunderstorms developing across the CWA later this afternoon and into this evening. Will continue to monitor for heavy shower and thunderstorm development. The NHC has the center of Hanna making landfall around Baffin Bay either late Saturday afternoon or early Saturday evening, with it turning more southwestward after landfall. Further strengthening of TS Hanna is looking more and more likely at this point, with NHC expecting a hurricane forming by the time it makes landfall. As of 4 PM CDT, Tropical Storm Warnings remain in effect across the lower Texas coastal waters, all of Jim Hogg, Brooks, Kenedy, and Willacy Counties, northern Hidalgo County, and coastal Cameron County. The main impact with TS Hanna for deep South Texas continues to be very heavy rainfall, which may produce life-threatening flash flooding. Model guidance consensus has shifted the heaviest precipitation slightly southward across the BRO CWA over the past 12 hours. The Weather Prediction Center (WPC) has included all of deep South Texas in a Moderate Risk of FFG exceedance for D2 (Saturday) and a Slight Risk of FFG exceedance for D3 (Sunday). Given all of this and the possibility of Hanna further strengthening, went ahead and increased QPF to reflect a general total rainfall accumulation between 5 and 10 inches, with isolated amounts up to 15 inches, across the CWA -- majority falling Saturday morning through early Monday morning. A Flash Flood Watch remains in effect for all of deep South Texas from 7 AM Saturday through 7 PM Sunday. Another impact from TS Hanna will be tidal runup and minor coastal flooding along the coast, with wave heights from swell and wind waves building between 8 (nearshore) and 15 (offshore) feet. As a result, surf conditions at local beaches of South Padre Island and Boca Chica will become extremely rough and dangerous, with strong rip currents, beginning this evening and continuing through the majority of the weekend. A Coastal Flood Advisory remains in effect from 4 AM Saturday until 7 PM CDT Sunday. LONG TERM (Monday through Friday): As the remnants of Hanna continue moving west over northern and central Mexico, broad weakness in the 500 mb pattern will prevail over the TX coastline. This in combination with the lingering tropical moisture over TX and the western Gulf of Mex will maintain the threat of conv throughout the first half of next week. After Wed, 500 mb ridging will then build back east over the TX coastline which will start shutting down the conv chcs over Deep South TX and the RGV during the last half of the work week as the airmass dries out and stabilizes. The cld cover and higher pops will likely hold down the overall temps to near or a little below climo through Wed with temps warming back up to above climo from Thurs through Sat. MARINE (Now through Sun Night): Buoy 42020 reported north winds around 14 knots, gusting to around 16 knots, with seas just above 4 feet with a period of 6 seconds at 1440 CDT/1940 UTC. Moderate northerly winds and seas will persist through the rest of the afternoon as Tropical Storm Hanna continues to progress westward into the northwest Gulf of Mexico. Marine conditions will become adverse beginning tonight with strong winds and increasing swell as Hanna approaches the lower Texas coast, making landfall near Baffin Bay early Saturday evening. Tropical storm force wind gusts are likely, especially across the northern Gulf and bay waters Saturday into Sunday morning. Tropical Storm Warnings remain in effect for all of the lower Texas coastal waters, including the Laguna Madre. Follow the latest updates on Tropical Storm Hanna from the National Hurricane Center. Mon through Wed: Surface ridging over the Gulf of Mex will maintain a light to moderate onshore flow pattern along the lower TX coastline next week with Bay condiions remaining below SCA levels through midweek. The lower TX Gulf waters may see some swells edging up into SCEC territory, but for now do not expect any SCA conditions. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 91 78 87 79 / 50 100 90 80 BROWNSVILLE 96 79 87 80 / 40 100 90 80 HARLINGEN 99 77 87 78 / 40 100 90 80 MCALLEN 98 79 88 78 / 30 90 90 80 RIO GRANDE CITY 100 80 92 77 / 20 90 90 80 SOUTH PADRE ISLAND 87 79 86 81 / 50 100 90 80 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...Tropical Storm Warning for TXZ249>251-254-256-257-351-353. Coastal Flood Advisory from 4 AM Saturday to 7 PM CDT Sunday for TXZ256-257-351. Flash Flood Watch from Saturday morning through Sunday evening for TXZ248>257-351-353. GM...Tropical Storm Warning for GMZ130-132-135-150-155-170-175. && $$ This product is also available on the web at: HTTP://WEATHER.GOV/RGV Aviation...67-Mejia
Area Forecast Discussion
National Weather Service Cheyenne WY
521 PM MDT Fri Jul 24 2020 .SHORT TERM...(This evening through Saturday) Issued at 230 PM MDT Fri Jul 24 2020 Leeside trough has pushed out into the Nebraska Panhandle this afternoon with downsloping northwest winds over southeast WYoming. So far...showers have been slow to get going over southeast Wyoming. Locations out west of the Laramie Range have been worked over with showers and cloud cover through the morning. Temperatures out there have been mainly in the mid 70s...while east of the Laramie Range...mid 80s have been common across the southeast Wyoming plains. Panhandle temperatures have climbed into the low 90s. Latest mosaic radar beginning to show convection developing over central Colorado near Denver and eastern front range...moving north northeast. Have not ruled out severe storms yet for the Panhandle this afternoon with those warm temperatures. SPC Mesoanalysis showing SB CAPE climbing into the 2000 J/KG range by late this afternoon. NAMnest and HRRR mesoscale guidance continue to show a few supercells possible...congealing into lines as the exit east into LBFs CWA. Looks like we may luck out though with severe storms just east of our Panhandle areas. Looks like an early evening with showers clearing the Panhandle after 03Z. Cold front approaches from the north Saturday morning with surface front near Cheyenne towards 12Z. Monsoonal moisture shunted south for Saturday into Colorado. Most shower activity looks to be along the Wyoming/Colorado state line and maybe out into the southern Panhandle. .LONG TERM...(Saturday night through Friday) Issued at 230 PM MDT Fri Jul 24 2020 Get another surge of moisture Sunday afternoon/evening into the CWA with fairly widespread convection across the eastern portions of the CWA Sunday afternoon into the evening hours. Look for daily chances of showers and thunderstorms through the upcoming work week. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 521 PM MDT Fri Jul 24 2020 VFR conditions expected at all terminals through the period with mid and high clouds dominating in monsoonal flow. Some showers and possibly a couple tstms affecting mainly KRWL and KSNY this evening with brief gusty winds possible from these. && .FIRE WEATHER... Issued at 230 PM MDT Fri Jul 24 2020 Minimal fire weather concerns the next several days as monsoonal moisture remains over the forecast area. Zone to watch for Saturday will be FWZ 301...where afternoon humidity could fall to critical during the afternoon. Winds however...look to be below critical levels Saturday afternoon. Monsoonal moisture makes another surge north into Wyoming Sunday into Monday for increased chances of afternoon and evening showers and thunderstorms. Drier conditions Wednesday/Thursday as a cold front from the north moves into the area shunting monsoonal moisture south into Colorado. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...GCC LONG TERM...GCC AVIATION...RE FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Lake Charles LA
1046 PM CDT Fri Jul 24 2020 .UPDATE... Hanna has continued to strengthen through the evening hours with max sustained winds of 65 mph on a westward course and looks to make landfall tomorrow afternoon/ evening. As a result have raised winds in the coastal waters as buoy`s are indicating sustained 20 to 25 knots with higher gusts. Hanna is expected to strengthen becoming a hurricane before landfall. As for the tides they are still about two feet above astronomical levels, the tide is currently falling slowly and this will continue to around midnight before an incoming tide develops into the overnight hours with a high tide around 7 to 8 am with the possibility again of reaching coastal flood advisory criteria. Hanna is projected to continue on a westward course once the storm moves inland. The heaviest rain threat will be along the coast with an elevated threat north of the I-10 corridor. Chances for rains will continue on Sunday and through the middle of the coming week. But afternoon temps will also moderate as a result of the clouds and rains. Minor changes to the coastal waters. && .PREV DISCUSSION... /issued 622 PM CDT Fri Jul 24 2020/ DISCUSSION... For the 7/25 00Z TAF Issuance. AVIATION...Outer rain bands from Hanna along with some modest surface based instability has allowed for a few bursts of tropical downpours across south central Louisiana. Trend has been for weakening and even dissipation of rain as it moves into southwest Louisiana. Coverage of rain should continue to decrease as per latest HRRR runs. Banding showers are expected to increase late in the overnight hours and into Saturday morning, especially over I10 corridor. For now, will maintain breezy east winds and ceilings mainly just above MVFR. Periodic light shower activity for TAFs near I10 corridor through most of the period. PREV DISCUSSION... /issued 410 PM CDT Fri Jul 24 2020/ SYNOPSIS... Tropical Storm Hanna will strengthen and move westward across the western Gulf of Mexico with the center making landfall around Corpus Christi, Texas Saturday afternoon. Occasional torrential downpours rotating around the outer circulation will bring a chance for some heavy rainfall. A Slight Risk, level 2 out of 4, probability of heavy rainfall leading to flooding for locations south of I-10 tonight, with a Marginal Risk, level 1 out of 4, probability of heavy rainfall leading to flooding for the remainder of the forecast area. Elevated tide levels will bring a chance for some minor coastal flooding during high tide times this evening along the entire coast, as well as coastal lakes, and again on Saturday morning for the southeast Texas and southwest Louisiana coast, as well as, coastal lakes. There is a Marginal Risk, level 1 out of 5, probability of Severe Weather tonight, into very early Saturday morning, right along the coast, for a non zero chance of brief spin ups with any rainbands that may form and rotate onshore. Rua DISCUSSION... Tropical Storm Hanna is strengthening this afternoon and is expected to continue a gradual strengthening trend until the center makes landfall, which is expected early Saturday afternoon along the lower Texas coast near Corpus Christi. This system has a large expanse of copious tropical moisture with it. Latest GOES blended precipitable water (PWAT) has values over the forecast area around 2.4 inches, which is near the SPC moving and daily max climo values. Therefore, the cyclonic flow around Hanna will continue to push highly anomalous moisture into the forecast area over the next couple of days, which will help bring high rain chances, with shower activity capable of producing brief torrential downpours. The shower activity should contract closer to the center during the night, with best chances near the coast, then expand inland during the daytime. Also, something to look at will be any rainbands that can form on the northern side of Hanna that may be able to rotate onshore. With increasing veering flow, there is a non-zero chance for a brief spin ups with any rainbands that can get going overnight into early Saturday morning. Also, with the easterly flow producing ekman spiral affect, which is usual with tropical system in the western Gulf, tides are running around 2 feet above astronomical predicted levels, and at high tide time are reaching above coastal flood advisory criteria. This should continue with the next high tide time this evening, then again for southeast Texas and southwest Louisiana for the high tide time on Saturday morning. The tides should begin to gradually decrease later on Saturday after the center of Hanna makes landfall. For the end of the weekend into next week, elevated rain chances look to continue as left over tropical-like moisture and a relative weakness aloft persist. Rua MARINE... Elevated winds and high seas around the outer circulation of Tropical Storm Hanna will continue over the coastal waters through the night into Saturday morning with a Small Craft Advisory in effect. Winds and seas will gradually decrease later on Saturday after Hanna moves further west and into Lower Texas. Rua && .PRELIMINARY POINT TEMPS/POPS... AEX 74 88 73 88 / 30 80 20 70 LCH 77 86 75 84 / 50 80 70 80 LFT 76 86 74 86 / 50 80 50 80 BPT 79 86 75 84 / 60 80 70 80 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...Coastal Flood Advisory from 7 AM to noon CDT Saturday for LAZ041- 073-074. TX...Coastal Flood Advisory from 7 AM to noon CDT Saturday for TXZ215- 216. GM...Small Craft Advisory until 7 AM CDT Saturday for GMZ455-475. Small Craft Exercise Caution from 7 AM CDT Saturday through Saturday afternoon for GMZ455-475. Small Craft Advisory until 1 PM CDT Saturday for GMZ450-452-470- 472. Small Craft Exercise Caution through Saturday afternoon for GMZ430-432-435. && $$ PUBLIC...19
Area Forecast Discussion
National Weather Service Memphis TN
824 PM CDT Fri Jul 24 2020 .UPDATE... Isolated to scattered showers and thunderstorms continue across the Mid-South this evening. The latest HRRR shows convection dying out by midnight. Expect another muggy night across the area with lows remaining in the 70s. Current forecast looks good. No further updates are expected. KRM && .DISCUSSION... /issued 243 PM CDT Fri Jul 24 2020/ Rinse and repeat through the weekend. Expect highs in the low 90s with overnight lows in the low to middle 70s. Afternoon heat indices will likely exceed 100 degrees. We may see slightly less coverage of thunderstorms tomorrow, but any location could see a storm resulting in locally heavy rainfall, lightning and gusty wind. However, it will provide a bit of relief from the heat. The chance of severe thunderstorms looks minimal. 30 && .Long Term Showers and thunderstorms can be expected through Monday. Temperatures during this time will remain into the upper 80`s and low 90`s with heat indices close to, if not exceeding 100F during the daylight hours. Nighttime temperatures will remain into the low to mid 70`s. The pattern changes as we head into the new work week. A trough digs in over The Great Lakes region. The ridge we are under shifts westward and amplifies over the Rockies on Sunday. A weak cold front as a result should pass through the Mid-South by Tuesday morning. This will bring a new round of showers and thunderstorms. Temperatures and humidity levels will drop slightly behind the front, spelling relief heading into August. SMW && .AVIATION... Diurnal convection will last another hour or two then mostly clear skies overnight then a repeat Saturday. Winds will generally be light overnight then south at 5-7 kts by Saturday afternoon. SJM && && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$
National Weather Service Morristown TN
924 PM EDT Fri Jul 24 2020 .UPDATE... EVENING UPDATE. && .DISCUSSION... Showers and storms have decreased in coverage over the past several hours but there is still a cluster of storms along the southern Cumberland Plateau that is producing quite a bit of lightning and torrential downpours. The latest run of the HRRR shows this area being the favored area for some linger convection over the next few hours. Have made some POP adjustments to keep these areas in chance POPs over the next few hours. Elsewhere, an isolated shower or storm remains possible through the night. Fog is once again expected across areas the received rain if we can get enough overnight clearing. Hourly temps were way off again this evening due to the earlier storms so have made adjustments. Also, lowered min Ts in a few spots based on latest temps and dewpoints. Will send out new zones. SR && .AVIATION... 00Z TAF DISCUSSION. As expected, showers and storms are decreasing with loss of daytime heating. Mostly quiet overnight, though a few isolated showers and storms still remain possible. VFR conditions expected at CHA through the period. Some areas will see fog tonight, especially those that received rainfall today. Amount of fog depends on overnight clearing so there are still some questions on how widespread. Currently, forecasting TYS to see MVFR fog during the early morning hours while TRI is expected to reach IFR levels. Then, more scattered showers and storms developing tomorrow afternoon areawide. && .PREV DISCUSSION... /ISSUED 317 PM EDT Fri Jul 24 2020/ SHORT TERM (Tonight and Saturday)... Convection will decrease in coverage after loss of daytime heating and the associated stabilizing of the atmosphere. Expect clearing conditions overnight with fog near areas that received rainfall. Upper ridging remains anchored across the middle of the nation with a 594-595dam upper 500mb ridge centered across Kansas and Missouri producing weak northerly flow across the region. Low level SE flow between a ridge across the Mid- Atlantic and Tropical Storm Hanna near south Texas. This will continue to produce an area of weak 850mb-700mb convergence across southern and central portions of the forecast area. Synoptic forcing is very weak on Saturday allowing mesoscale factors to be the primary contributors to convective development and organization. With daytime heating, instability will be on the increase with NAM soundings showing MLCAPE between 1500 to 2500 J/Kg by early afternoon. With differential heating along the higher terrain, thunderstorm initiation is expected by midday. Pulse convection will be the primary mode with deep layer shear less than 10 kt. In addition, DCAPE values will be higher on Saturday which may enhance the risk of isolated microbursts with descending thunderstorm cores. HREF guidance shows low-level moisture will remain high with PW values across the southern half of the forecast area between 1.8 to 2.0 inches contributing to locally heavy rainfall and isolated flooding. Convective coverage will follow a diurnal curve with a decrease in activity during the late evening and early overnight hours. JB LONG TERM (Saturday night through Friday night)... Through the weekend, an elongated ridge of high pressure aloft will stretch from the southern plains east through the mid Atlantic. A northern stream shortwave will move through southern Canada and the northern plains. Typical summertime weather will result with afternoon scattered showers and thunderstorms expected. Temperatures near to slightly above normal can be expected Saturday night and Sunday. On Monday, the northern stream shortwave drops out of southern Canada and into the Great Lakes with an attendant cold front moving through the Ohio valley. Lower heights and southerly low level flow will enhance precipitation chances Monday and Monday night before the cold front approaches on Tuesday. Increased cloud cover and precipitation should keep temperatures slightly cooler on Monday. Frontal passage occurs on Tuesday and Tuesday night. Upper disturbance ejects northeast allowing the cold front to weaken as it moves through the region. Coverage of showers and thunderstorms should pick up on Tuesday with this period likely having the highest PoPs. Start to see model diverge regarding the strength of the ridge across the southeast. The ECMWF seems to break the ridge down more with a more amplified pattern while the GFS keeps the ridge, although still weak. However, guidance does agree that northwest flow will setup across the Tennessee valley toward the end of the period with continued chances of showers and thunderstorms and near normal temperatures. Diegan && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 73 92 72 91 73 / 30 40 20 50 20 Knoxville McGhee Tyson Airport, TN 70 90 71 91 72 / 20 30 20 50 20 Oak Ridge, TN 70 90 70 91 71 / 20 40 20 50 20 Tri Cities Airport, TN 66 89 67 89 68 / 30 30 20 50 20 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$
Area Forecast Discussion
National Weather Service New York NY
1111 PM EDT Fri Jul 24 2020 .SYNOPSIS... A frontal boundary will slowly move south of the region tonight. High pressure then will be in control of the weather through the weekend. Another cold front will move across the area during the middle of next week with high pressure building back across the region for the end of the week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... A frontal boundary will move farther south of Long Island tonight with high pressure gradually building in behind it from the north. Expecting clouds to diminish to start the overnight period, but return with low level stratus overnight into early Saturday as indicated by HREF and HRRR across parts of the Lower Hudson Valley, parts of Northeast NJ, parts of Southern CT and much of NYC and Long Island. Forecast also has patchy fog overnight for Long Island, Southern Westchester NY, and Southern Connecticut with light to calm winds and moisten laden grounds. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Weak high pressure remains over the region during the period. Some CAMS show showers popping up in the afternoon along sea breezes and differential heating near our westernmost zones. Thinking is we remain dry with dry mid levels and sufficient capping near 750- 800mb. 850mb temps of around 16C will lead to highs in the mid 80s to around 90. Surface dewpoints should be able to lower a couple of degrees before sea breezes push them back up. Heat index values therefore around 90 in most spots, and just under 95 for parts of NE NJ, the Lower Hudson Valley, and parts of the City. Dry weather then continues Saturday night with lows in the 70s across most areas. && .LONG TERM /SUNDAY THROUGH FRIDAY/... High pressure builds across the region on Sunday and dominates the weather through the beginning of the week. A SW flow will advect warmer and a more humid air mass across the area. As a result temperatures Sunday through Tuesday will be in the low to mid 90s and a few locations could very well have another heat wave Sunday through Tuesday. Forecast grids for max heat index have a large part of the area in the mid 90s to near 100 for Sunday, Monday and Tuesday. Heat Advisories are possible Sunday through Tuesday. Showers and thunderstorms are forecast to develop Tuesday into Tuesday night with the hot and humid airmass in place and ahead of an approaching cold front. The instability and high precipitable water will allow for thunderstorms to potentially be strong with heavy downpours. The cold front should start to push offshore by late Wednesday as high pressure begins to build in allowing for drier conditions through the end of the week. Temperatures on Wednesday and Thursday will be in the mid to upper 80s with temperatures on Friday in the low to mid 80s. There is a moderate risk of rip current development at the Atlantic Ocean beaches on Sunday. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... A frontal boundary will move farther south of Long Island tonight. High pressure will gradually build in from the north tonight and remains Saturday. Mainly VFR with isolated MVFR to IFR going into overnight with MVFR to IFR expected to redevelop in a larger area late overnight into early Saturday morning in fog and low stratus, generally 08-13Z. This time window could be off by a few hours with the start time. VFR expected to return after 13Z Saturday and prevail through the remainder of the TAF period. Winds near 5kts or less with a S direction for coastal terminals and nearly calm for terminals farther inland. Direction will eventually become more NW late overnight into early Saturday. Winds become a variable direction again Saturday morning before increasing to 5-10 kts during the day Saturday with sea breezes likely. .OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY... .Saturday night through Monday...VFR. .Tuesday...Chance afternoon and evening showers/tstms with MVFR or lower possible. .Wednesday...Mainly VFR. && .MARINE... Some patchy fog is expected to develop overnight into early Saturday morning for much of the forecast waters except for NY Harbor. Winds and seas across the forecast waters will remain below SCA levels through the forecast period. && .HYDROLOGY... Heavy rain and minor flooding are possible with thunderstorms Tuesday into Tuesday night. && .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. && $$ SYNOPSIS...JC/Fig NEAR TERM...JC/JM SHORT TERM...JC LONG TERM...Fig AVIATION...JM MARINE...JC/Fig/JM HYDROLOGY...JC/Fig EQUIPMENT...