Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/13/20


AREA FORECAST DISCUSSION
National Weather Service Albany NY
1016 PM EDT Mon Oct 12 2020 .SYNOPSIS... A widespread rainfall will develop tonight and continue into Tuesday afternoon as a front approaches from the west. High pressure will build in behind the front returning fair weather to the area through mid week. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... As of 1000 PM EDT...Main update was to lower PoPs/QPF further based on trends and per 00Z HRRR (thoughts are the NAM remains a bit too aggressive). Main reasons below remain the same at this time... As of 730 PM EDT...Layered H2O vapor loop depicts ample dry air in place with some hints of the lower layer channel of some moistening up the past hour. Local 0.5 degree radar scan shows some weak returns, likely virga, into Dutchess and Litchfield Counties. A quick look at the 00Z sounding data, quite a bit of dry air just below H900. So with this update, we will reduce and delay the onset of PoPs/Wx for next couple of hours. Thereafter, low level easterly trajectory increases which should advect in more lower level moisture and approach of upstream trough for added synoptic lift for widespread wet conditions to evolve. Prev Disc...Widespread rainfall will develop tonight especially after midnight as ridging across the region retreats and an upper trough and its associated front approach from the west. With the surface high over the Canadian Maritimes and the remnants of TC Delta along the mid Atlantic coast, southeast flow in the low levels will be strengthening and moisture from Delta will be tapped. This rain will be beneficial. East-southeast winds will gusts up to 25 to 30 mph in favored higher terrain areas especially across western New England and the Taconics. Expecting lows in the 40s across the area. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... Rain will continue well into Tuesday afternoon as the upper level trough and its associated occluded boundary move across the region and the remnants of Delta pass well to our south across Long Island and the Cape Cod. Rainfall will get enhanced across New England with broad ascent as heights falls across the region as the upper trough swings through. The rain will taper off west to east with the passage of the boundary. Having some lingering pops into the early evening to the east the Hudson River Valley. Decreasing clouds Tuesday night with some fog expected. Will be cool Tuesday with highs only in the 50s. Flow aloft becomes flat while at the surface ridging builds in and shifts across the region Wednesday. The center of the high will pass to our south shifting off the mid-Atlantic and southeast coast Wednesday night. Seasonable temperatures are expected with light winds and sunshine. && .LONG TERM /THURSDAY THROUGH MONDAY/... The flow pattern during the long term will feature a broad anomalous trough centered over the Plains states shifting eastward and becoming negatively tilted. Locally, the period will start out mild on the downstream side of the trough axis. A surface low moving northeastward through Quebec will pump mild air into the region, with highs forecast to be several degrees warmer than normal. Showers will gradually increase along the front from west to east through the forecast area Thursday evening into Friday. The main source of uncertainty is how sharp the troughing becomes as the axis pivots into the Northeast. Both the deterministic ECMWF and GFS have more or less held to their respective solutions over the last several runs, with the former spinning up a strong cyclone in the vicinity of Long Island/southern New England as the trough becomes sharply negatively tilted, while the latter spins up a weaker cyclone moving into Maritime Canada. Enough confidence at this point for likely PoPs Friday/Friday night, but with low confidence on the details. An ECMWF-style solution would present the possibility of heavy rainfall over portions of the forecast area and perhaps some snow over the higher terrain, while the GFS solution is more innocuous. GEFS members show rather good clustering around the deterministic solution. Not much to say about which camp will be correct at this point, so will stick to NBM guidance. Temps likely return to near/below normal behind this system for Friday into next weekend. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... Through 00z/Wed...VFR conditions to the north of KPOU as MVFR ceilings will advance northward the next few hours to KPSF- KALB-KGFL. As light rain unfolds, ceilings and visibilities will lower to borderline IFR/MVFR through most of the overnight period. Of increasing concern, as suggested and briefed from previous forecast, LLWS from the easterly direction appears to be an issue as we will add these to the TAFS overnight into early Tuesday morning around sunrise. Rain/showers will likely persist most of Tuesday til about mid-late afternoon hours. Here, conditions will likely remain MVFR with respect to ceilings and visibilities to VFR. Winds will be challenge for the Hudson Valley locations where southeasterly direction less than 10kts, may become northerly overnight. For KPSF, easterly winds will increase with gusts at or above 20kts expected. Northwesterly winds evolve during Tuesday daylight hours. Outlook... Tuesday Night: Low Operational Impact. Patchy FG. Wednesday: No Operational Impact. NO SIG WX. Wednesday Night: No Operational Impact. NO SIG WX. Thursday: No Operational Impact. NO SIG WX. Thursday Night: Moderate Operational Impact. Chance of SHRA. Friday: Moderate Operational Impact. Likely SHRA. Friday Night: Moderate Operational Impact. Likely SHRA. Saturday: Moderate Operational Impact. Chance of SHRA. && .FIRE WEATHER... A widespread rainfall will develop tonight and continue into Tuesday afternoon as a front approaches from the west. High pressure will build in behind the front returning fair weather to the area through mid week. Winds tonight into Tuesday will be easterly around 5 to 15 mph, with some occasional gusts of 25 to 30 mph in favored higher terrain areas. Winds on Tuesday will shift to the northwest-west at around 5 to 10 mph. && .HYDROLOGY... No widespread or significant hydro problems are expected through the next 7 days. Beneficial rainfall overnight into Tuesday afternoon with moisture from the remnants of TC Delta being tapped. Total rainfall amounts through Tuesday are forecast to range from around 1/2 to 1 inch in most locations, with up to 1 1/4 inches across favored higher terrain areas of the southern Green Mountains of VT. Brief high rainfall rates at times may produce some ponding of water on roadways. Some increased river flows are likely, but are not even expected to reach action stage at any main stem forecast points. Drier weather looks to return Tuesday night through Thursday, which will result in decreasing river flows. For details on specific area rivers and lakes, including observed and forecast river stages and lake elevations, please visit the Advanced Hydrologic Prediction Service /AHPS/ graphs on our website. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...IAA NEAR TERM...IAA/BGM SHORT TERM... LONG TERM...Thompson AVIATION...BGM/Rathbun FIRE WEATHER...IAA HYDROLOGY...IAA
Area Forecast Discussion
National Weather Service Columbia SC
1038 PM EDT Mon Oct 12 2020 .SYNOPSIS... A weak and dry frontal boundary will cross the area Tuesday with high pressure will building into the region for Tuesday night through Thursday. Another cold front will move into the area late Thursday night and Friday with a few showers. && .NEAR TERM /THROUGH TUESDAY/... The remnants of Delta are now off the Mid-Atlantic coast, but a trailing cold front extends southwest across the Pee Dee and into northern/central Midlands. Not much of an airmass change with this boundary, with more of a northwest to north flow noted behind the front along with slightly lower dewpoints. Satellite imagery depicts extensive cloud cover still in place across much of the area, with some isolated showers mainly along and southeast of the boundary, affecting portions of the far eastern Midlands this evening. The deeper moisture should shift eastward later this evening and overnight, bringing an end to any remaining showers and allowing skies to at least partially clear. Lingering low level moisture, light winds and clearing skies should promote the formation of some fog toward daybreak. The NBM, HRRR and ARW/NMM all suggest the best coverage north of the front, so have included mention of areas of fog across the northern/central/eastern Midlands, with patchy fog elsewhere. Locally dense fog is possible as well, and conditions will need to be monitored through the night for potential dense fog advisories. Another mild night is expected, with lows in the 60-65 range. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... A cold front will cross the forecast area on Tuesday as an upper trough moves eastward through the Mid-Atlantic region and off the coast by Tuesday evening. Moisture is quite limited with this front with PWAT values around an inch or less and decreasing through the day from northwest to southeast. Cannot rule out an isolated shower over the eastern Midlands with daytime heating where moisture is a bit deeper but confidence is low so will continue with a dry forecast at this time. Behind the front, a slightly cooler and drier air mass will arrive as high pressure builds over the region through Wednesday. Surface high pressure will begin to shift offshore on Thursday as return southeasterly flow allows moisture to return to the region. Do not think there will be enough moisture return and lift to result in showers at this time but pops may need to be added in future forecasts if the moisture returns quicker or deeper than expected or if the coastal trough is stronger. So for now will carry a dry forecast. Temperatures will still be on the warm side on Tuesday as the cooler air will be slow to work in with highs in the 80s. Overnight lows Tuesday night will range from the mid 50s northwest to lower 60s southeast. Highs on Wednesday will be cooler ranging from the upper 70s northern Midlands to the lower 70s in the CSRA. Temperatures moderate a bit on Thursday as flow picks up a southerly component again ahead of the next upper trough and a more significant cold front approaches. && .LONG TERM /FRIDAY THROUGH MONDAY/... A transition to a much cooler and drier period is expected during the extended period. A digging upper trough over the Great Lakes and Ohio Valley will drive a cold front through the forecast area on Friday. The frontal system appears to be a bit limited on moisture along the front so confidence is low on any precipitation being associated with the frontal passage as PWATs will only be around an inch. Will continue to carry slight chance pops mainly across the northeastern part of the forecast area at this time. The front will usher in a much cooler and drier air mass as surface high pressure originating in western Canada will build over the forecast area Friday night and Saturday and remain in place through the weekend. Another reinforcing dry front may pass through the region on Monday with very limited moisture. Temperatures during this period will be near to slightly below normal for highs and below normal for lows. Saturday and Saturday night appears to be the coolest day of the extended period. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... VFR at all terminals with the exception of AGS, MVFR/IFR conditions likely until shortly after daybreak. Skies have cleared across SC/eastern GA, with clouds building in from the north later on in the evening. Winds expected to become calm all TAF sites over the next few hours. With moisture still present in the area and moderate subsidence, fog is expected to develop at all terminals. High resolution models are showing a deep surface inversion forming overnight due to the lack of cloud coverage at AGS/DNL. Due to this, LIFR fog that has formed at AGS will likely persist until morning. Conditions elsewhere will start to decrease around 10z. Considering the calm winds and current radiational cooling at CUB/CAE/OGB, LIFR vis/cigs are expected prior to daybreak. Winds should pick up quickly after, so kept MVFR/IFR conditions until around 15z. Winds will be from the NW later on in the afternoon 5-10kts. EXTENDED AVIATION OUTLOOK...Little impacts to aviation expected through Friday associated with a dry cold front and high pressure. && .HYDROLOGY... Recent rain and upstream releases will lead to minor to moderate flooding along portions of the Congaree, Wateree and Pee Dee Rivers. For more information, go to weather.gov/cae && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$ SYNOPSIS...99 NEAR TERM...99 SHORT TERM...99 LONG TERM...99 AVIATION...99 HYDROLOGY...
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
717 PM CDT Mon Oct 12 2020 .UPDATE... Issued at 715 PM CDT Mon Oct 12 2020 The Red Flag Warning has been cancelled this evening as wind speeds have decreased. Relative humidity have risen and will continue to increase tonight as temperatures cool. && .DISCUSSION...(This evening through Monday) Issued at 353 PM CDT Mon Oct 12 2020 A progressive shortwave trough has long since exited to the east, and the associated cold front has scoured out some clear smokeless skies today. After some pretty good mixing above 800 mb today, wind speeds should calm down as we begin to decouple and the surface pressure gradient relaxes. The flow continues to be progressive and yet another cold front will come through late tonight (although not nearly as strong as the one that passed through Sunday evening). Nonetheless this does look like a dry frontal passage and confidence is high for this. Both the NAM12 and RAP indicate pressure rises of 3-4 mb/3 hrs behind this cold front between 09Z and 15Z, so I would not be surprised to get a 20-25 mph wind gusts from the northwest directly behind the front Tuesday morning. By afternoon, surface high pressure settles in and wind will become noticeably lighter. With highs in the lower 70s and dry weather with light wind, Tuesday afternoon would be ideal fall weather conditions for many people. On Wednesday, yet another cold front passage is expected, and this time, height rises behind the front will be in the 4-6 mb/3-hr realm. Looks like I will be bumping wind/wind gusts a good 5 mph or so from the current forecast as we are trending quite breezy. The ECMWF forecasts wind gusts up to 45 mph for areas just northwest of the tri-cities for Wednesday afternoon and this looks quite believable given how dry we look. The highest gusts probably will not last too long, however, and will shift south with time. Not sure if we will not see a sprinkle or two at some point Wednesday night with the potential of a quick-hitting wave, but the ECMWF does seem to indicate this as a potential. By Thursday, the jet stream take a notable dip to the south and will wind up being a chilly day with forecast highs in the 50s. Winds will lighten up by Thursday night with surface high pressure settling in, and widespread frost is anticipated. Dry weather will continue into the weekend, with rather cool-ish fall weather forecast. The GFS indicates a cold front could come through to make Sunday and beyond colder than what we have in the forecast as 850 mb temps are forecast to be near -10C or so. the ECMWF waits until Monday, and for now, I will side with the later ECMWF side. If we are closer to the GFS solution, we might be able to get a dusting of snow Sunday, however. Monday does look quite windy with strong surface pressure rises behind the cold front, and although still a little early to be talking snow, Monday night there could be potential and I suspect that the potential might be better Monday night as compared to Sunday night. Anomalously cold air looks like it will potentially bust through behind the strong cold front on Monday and 850 mb temps are generally forecast in the -5C to -10C range from ensemble data for Monday/Monday night. More than cold enough to support snow, given that we have some precip around. Our highs in the 50s from the previous forecast may be in jeopardy as this might be relying way too much on climatology. Hard to tell this far out as timing of cold air intrusion will mean everything for Monday highs. Nonetheless, if cold air is in place (and I have high confidence that it will be), some ECMWF model ensemble members indicate some light snow in our future. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday) Issued at 557 PM CDT Mon Oct 12 2020 VFR conditions are forecast through the TAF period. Surface wind speeds will drop off this evening but remain strong aloft, leading to several hours low level wind shear. A cold front will cross the terminals tonight, bringing a wind shift to the north/northwest. Tuesday morning will see a period of gusty winds behind the front, but the gradient will relax during the day as surface high pressure settles onto the plains with winds becoming light by aftn. && .FIRE WEATHER... Issued at 253 PM CDT Mon Oct 12 2020 Red Flag Warning looks good. Not much margin for error, but looks like it will work out as wind gusts should be somewhat more muted just east of the tri-cities. Next chance of fire weather issues will be Wednesday as wind gusts pushing 40 mph are possible as relative humidity drops to critical to near-critical levels. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...Fay DISCUSSION...Heinlein AVIATION...Fay
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
825 PM CDT Mon Oct 12 2020 .UPDATE... 824 PM CDT Had updated forecast earlier to remove the remnants of clouds and showers which moved out of the area by early evening. Current forecast looks to be in good shape into Tuesday, and no additional changes are needed at this time. Surface cold front which moved through the region earlier today has pushed well east of the area this evening. Surface high pressure has spread into the lower Missouri Valley in the wake of the strong disturbance today, with the northeastward periphery of the ridge axis moving across the Mississippi toward IL late this evening. Clear skies and a dry post-frontal air mass behind the front (surface dew points falling into the upper 30s across the western cwa) have allowed a quick cool-down with the loss of mixing at sunset, with winds having diminished quickly as well. Forecast temps in the upper 30s to around 40 (mid 40s in the heart of the Chicago urban core) overnight appear reasonable given the scenario. Warm advection begins aloft after midnight already as the next in a series of quick waves approaches from the northwest late tonight. Winds turn southwest by morning, and become breezy/gust after sunrise. Patchy mid clouds will likely affect especially northern parts of the cwa late morning through midday, though a good amount of sunshine will support temps warming back into the low 70s in most areas with the breezy southwest winds. Peak gusts 30-40 mph will again diminish quickly toward sunset. Ratzer && .SHORT TERM... 340 PM CDT Through Tuesday night... After the active autumn cold front of today, the weather focus in the short term shifts to the critical fire weather conditions expected on Tuesday, most notably along and south of I-80. A continued impressive presentation on satellite imagery of the trough from the Upper Midwest/western Great Lakes through the mid-Mississippi Valley. The pronounced slightly negatively-tilted short wave and associated speed max is moving directly over the CWA as of 330 PM and the surface cold front has cleared the CWA. The low-topped convection, even supercellular at times with 1-3 km rotation noted on adjacent radars, has also cleared the forecast area. The highest isallobaric component to the wind, associated with around 4 mb per 2 hr pressure rises, is moving quickly through the area behind the cold front. The highest gusts of around 35 mph (earlier 40-45 mph) are limited in spatial extent and duration, likely due to lingering stratus. There have been spotty gusts to 30 to 35 mph in the immediate clearing area moving into north central Illinois. Winds will continue to abate this evening and with the drier air mass and the cold advection from this afternoon, allow temperatures to drop at decent haste. Winds look to turn southwesterly late and start inching up especially in north central Illinois. Before that though some outlying areas could dip into the mid 30s and realize patchy frost. Tuesday will find another progressive short wave trough scooting across the international border ahead of a 115 kt jet maximum. While the surface low of around 1000 mb will be well north near Lake Superior, the translating pressure gradient will induce pressure falls across the area coincident with peak heating. The 925 mb temperatures of 14-15C over the area are easily supportive of temperatures into the mid 70s especially in the presence of warm advection and a dry lower troposphere. Model soundings continue to support the boundary layer effectively mixing, with southwest gusts of 30-35 mph and probably isolated 40 mph. One fly in the ointment hinted at is some mid to high clouds, but the pattern would favor those to remain mainly over Wisconsin. With the forecast profiles, dew points should mix down at least a few degrees in the afternoon, with RAP and NAM guidance keying in the southeastern half of the forecast area to even flirt with lower 30s dew points. These values provide relative humidities of 20 to 30 percent, with more than enough winds for critical fire weather conditions. Rain values today were primarily 0.15 to 0.40 of an inch, which with recent dry conditions and low fuel moisture values beforehand may just dry out very quickly Tuesday morning. Did consider a Fire Weather Watch but confidence was not there for that at this time, but confidence is high in at least near Red Flag Warning conditions especially south. Will continue to message windy and dry conditions in the Weather Story and ramp up additional points to consider canceling any planned burns. MTF && .LONG TERM... 340 PM CDT Wednesday through Monday... Expecting another breezy day on Wednesday as winds increase out of the southwest ahead of developing low pressure system and associated cold front across the upper Midwest. With ample warm air advection, expect temperatures to warm into the 70s for most areas. The trailing cold front will push across the area overnight with low rain chances developing behind the front early Thursday morning and increasing through the afternoon. As the low departs to the northwest on Thursday a cold airmass will advect over the Great Lakes region with high temperatures in the 50s expected across the local area Thursday and Friday. Low temperatures may drop to near freezing for areas outside of the Chicago metro on Thursday where some areas could see their first freeze of the season. Slightly elevated winds Thursday night and increasing cloud cover Friday night may limit our widespread freeze potential, however. Plenty of model variability remains for for the upcoming weekend, but generally expect cool conditions to continue through the remainder of the extended with the upper trough close by. Petr && .FIRE WEATHER... 400 PM CDT Gusty winds and both dry air and fuel moisture on Tuesday will support critical fire weather conditions, possibly to the level of a Red Flag Warning...mainly along/south of I-80. Confidence is high in sustained surface-to-20 ft southwesterly winds of 15-20 mph with surface gusts at least to 30 mph (some to 35+ mph possible) especially earlier in the afternoon. Our confidence also is high in relative humidity dropping to around 25 percent along and south of I-80, and may do so even north. The fuel moisture is a little more in question only because of today`s 0.15 to 0.40 inch of rain, though that is already getting some drying the rest of today and will also dry in the morning thanks to sun and increasing winds. One question is if the highest winds and lowest humidity can overlap in the afternoon, at Red Flag conditions if they occur may only be brief. Fire weather partners should monitor the latest fire weather forecasts (FWF) closely into Tuesday, as well as Wednesday which will also be breezy and dry, and consider any extra precautions that will be needed. MTF && .AVIATION... For the 00Z TAFs... Aviation forecast concerns: * Strong west-southwest winds Tuesday with gusts around 30 kt. Surface cold front which moved through the terminals earlier today has moved well east of the forecast area early this evening. As expected, skies have cleared quickly in the wake of the strong mid-level wave associated with the front. Clear skies, much drier air and loss of mixing as sunset approaches is already resulting in a quick decoupling of the boundary layer and a fast drop off in winds. West northwest winds 10 kt or less will gradually shift light southwest later tonight. The next in a series of quick-moving weather disturbances will approach the region early Tuesday, with southwest winds increasing and becoming gusty during the morning. Strongest winds are likely midday into the afternoon, with gusts around 30 kt likely during the hours of peak diurnal mixing. Some patchy mid-level cloud cover in the 12-15 kft layer are expected, and if these are thicker or more expansive than anticipated it could limit peak wind gusts somewhat, or at least make them more sporadic. Winds are expected to gradually diminish and turn westerly late in the afternoon, before shifting northwest by early evening as the surface cold frontal trough moves through. Winds should again diminish quickly with sunset. No precipitation is expected with this frontal passage. Ratzer && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...Small Craft Advisory...Burns Harbor to Michigan City IN until 1 AM Tuesday. && $$ Visit us at weather.gov/chicago Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/NWSChicago www.twitter.com/NWSChicago www.youtube.com/NWSChicago
Area Forecast Discussion
National Weather Service Las Vegas NV
858 PM PDT Mon Oct 12 2020 .SYNOPSIS...Dry warm weather will continue the next several days under a persistent area of high pressure. Temperatures will remain 5 to 10 degrees above mid October normals. && .UPDATE...Light winds, clear skies and above-average temperatures continue this evening. HRRR Smoke as well as satellite imagery from this afternoon indicated a smoke plume making its way down into the Owens Valley late this afternoon. That said, observations at Bishop Airport have not dipped below 10 statute miles, and area webcams indicated that the smoke layer was decently lofted just before sunset. Lofted smoke expected to continue through the rest of the evening, sink to the surface and lower visibility through the overnight hours in Owens Valley. Forecast looks to be in good shape tonight; no changes necessary. && .PREVIOUS DISCUSSION... 200 PM PDT Mon Oct 12 2020/ .DISCUSSION...through next Monday. Very little change in the warm dry weather pattern is indicated the next several days and no significant weather impacts are expected. This is due to a persistent ridge of high pressure extending from the Eastern Pacific over the Desert Southwest. We will see a few subtle changes such as north breezes filtering down through southern Nevada and the Colorado River Valley Thursday in response to a fast moving disturbance brushing the Great Basin as it moves down the front side of the ridge into a deep trough over the central U.S. This will be accompanied by high temps dropping 5-7 degrees Thursday and Friday. Temperatures then climb a few degrees over the weekend under the dry northwest flow aloft. && .AVIATION...For McCarran...Winds will remain light and follow near to diurnal trends for the period, remaining below 10 knots. Mostly clear skies expected through the period. For the rest of southern Nevada, northwest Arizona and southeast California...Other than some northerly breezes down the Colorado River Valley, look for winds to remain under 10 kts through Tuesday. Smoke from California wildfires is once again expected to work into the Owens Valley overnight with vsby potentially dropping to around 5-6SM through 15Z before increasing. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ UPDATE...Varian DISCUSSION...Adair AVIATION...Gorelow For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter