Area Forecast Discussion
Issued by NWS Buffalo, NY
Issued by NWS Buffalo, NY
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309 FXUS61 KBUF 171431 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 1031 AM EDT Mon Jun 17 2024 .SYNOPSIS... A warm front will pass east of our region, ushering in summer`s heat and humidity. Hot and humid through at least Thursday with apparent temperatures during this time likely to reach 100F at several locations Tuesday and Wednesday. A few isolated showers and thunderstorms during the afternoon each day, with more coverage area to storms later in the week. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... Showers associated with the warm front have weakened rapidly, with radar showing a few light returns in Oswego County. These should continue to dissipate by noon, leaving the forecast area rain-free through early afternoon. However, another convective shortwave across central Lake Erie will move east into Western NY mid to late afternoon. This will weaken with a 500mb ridge building overhead, but with plenty of instability in place this will have the potential to spark a few afternoon thunderstorms across Western NY, with these more likely to develop on lake breeze boundaries. Coverage should be scattered in nature, with the southwesterly lake breeze helping keep the city of Buffalo rain-free. Heat Details... The surface pressure gradient will increase with the passing of the shortwave aloft, with a bit of a southwesterly breeze in the 20 mph range. While not a great magnitude, this southwesterly flow behind the departed surface high will increase moisture advection through the day, with humidity notably higher through the afternoon hours. In the wake of the warm frontal passage temperatures today will also be notably warmer as 850 hPa temperatures increase to the upper teens to around 20C. Apparent temperatures will rise into the upper 90s in the lower Genesee Valley and Western Finger lakes region, where a Heat Advisory begins noontime. Elsewhere, will be hot with high temperatures in the upper 80s and apparent temperatures in the lower 90s. Tonight will be warm and muggy. Lows only in the upper 60s to lower 70s. Mainly fair weather after evening convection wanes, but a stray shower cannot be ruled out within this muggy and still unstable atmosphere. Where it rains in the Southern Tier today and within the valleys patches of fog are possible tonight. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... ...Heat Advisory in effect for the entire area as dangerous heat builds through mid week... Surface high pressure will remained anchored along the eastern seaboard as a slow amplification of the eastern CONUS ridge takes place during the period. This will result in a deep southerly flow which will bring HOT and HUMID conditions during the day and WARM and MUGGY conditions at night. Mid level ridge builds into the region Tuesday with 850 mb temperatures climbing to +20C. This will allow surface temperatures to soar into the lower 90s across the region with valley locations reaching the mid to upper 90s. Surface dewpoints will climb into the upper 60s to lower 70s with PWAT values 1.5 inches or greater. The combination of the heat and humidity will send apparent temperatures into the upper 90s to lower 100s from midday through the afternoon. Some scattered afternoon convection could develop as diurnal instability increases within the heat, with initiation along a lake breeze boundary or across higher terrain. Any convection will wane into the evening hours. The very warm airmass will persist through Tuesday night with overnight lows only dropping into the lower to mid 70s for most locations. Mid level ridge will be firmly in place Wednesday with ensembles showing heights around approaching 600 dm. 850 mb temperatures stay around +20C. With the region underneath the ridge, chance of convection should be less than Tuesday, potentially making Wednesday a HOTTER day than Tuesday. Most high temperatures again in the lower 90s across the region with valley locations reaching the mid to upper 90s, with apparent temperatures in the upper 90s to lower 100s from midday through the afternoon. && .LONG TERM /THURSDAY THROUGH SUNDAY/... ...Dangerous Heat Wave Will Continue For The Region Through At Least Thursday... Model consensus shows the axis of the anomalously strong nearly 600 decameter ridge will be just to our south and southeast Thursday, just a slight jog from its position on Wednesday. This may bring 500 mb heights down just a smidge, along with surface temperatures/dew points possibly a couple of degrees cooler. All in all, very similar to the hot and steamy conditions expected for Tuesday/Wednesday, which will make Thursday the most oppressive day of the long term period with heat index values again ranging from the mid 90s to very low 100s for the bulk of western and northcentral NY. Positioning/proximity of the upper level ridge will suppress most, if not all convection, especially across western NY. Better chance for an isolated shower/storm would be toward the North Country/Saint Lawrence Valley closer to the northern periphery of the ridge. A very gradual day-to-day `cooling` is then expected for the Fri-Sun timeframe as successive shortwaves traversing eastward through central and eastern Canada slowly suppress the ridge to the south, leaving a quasi-zonal flow in place across the CONUS by the end of the period. That said, still want to emphasize that conditions are still going to remain very warm to hot with elevated humidity levels. In terms of temperatures, upper 80s/low 90s Friday will slowly trend downward to the mid and upper 80s by the end of the weekend, with the highest elevations several degrees cooler respectively on any given day. Heat index values will reach the low to mid 90s for all of the lower terrain Friday afternoon, upper 80s to low 90s Saturday afternoon, and mid 80s to near 90 by Sunday. In terms of precipitation, there will be some increase in convection potential as we close out the work week and head into next weekend. This will be owed to mainly two things: Upper level disturbances riding the northern periphery of the upper ridge passing closer and closer to the area as the center of the ridge slowly sags further south through the period, while a surface boundary also sags south toward the region from Canada. Areas that do receive some showers/storms, will enjoy some relief, however any reprieve will only be temporary. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... For the 12Z TAFS, VFR flight conditions are found and these conditions are expected to remain through the end of the TAF cycle with surface high pressure nearby. There will be a slight southwest breeze this afternoon for KIAG and KBUF off Lake Erie, and southwest breeze for KART off Lake Ontario. Gusts will end in the 22-00Z timeframe. There will be a low chance for afternoon convection on lake breeze or terrain induced boundaries this afternoon...generally across the inland Southern Tier and into the Finger Lakes region. Outlook... Tuesday through Friday...VFR, but a slight chance for afternoon thunderstorms inland from the lakes. && .MARINE... High pressure will be near the eastern Great Lakes through much of this week, offering light winds, generally 15 knots or less on the lakes. && .CLIMATE... A prolonged period of heat is expected for our region, starting Monday June 17th. Below are record high temperatures for our three main climate sites: ...Buffalo... ...Date.....Record Maximum (F)...Record warm Minimum (F)... ...June 17........94/1994............73/2006 ...June 18........95/1994............73/2006 ...June 19........90/2001............73/1919 ...June 20........92/1995............73/2012 ...Rochester... ...Date.....Record Maximum (F)...Record warm Minimum (F)... ...June 17........94/1994............70/1994 ...June 18........97/1957............72/2018 ...June 19........95/2001............72/1919 ...June 20........95/1953............72/1923 ...Watertown... ...Date.....Record Maximum (F)...Record warm Minimum (F)... ...June 17........89/1994............68/1949 ...June 18........91/1957............70/1992 ...June 19........91/2007............70/1949 ...June 20........90/1971............71/2012 Temperature records for Buffalo and Rochester date back to 1871. Temperature records for Watertown date back to 1949. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...Heat Advisory from noon Tuesday to 8 PM EDT Thursday for NYZ001-002-006>008-010>012-019>021-085. Heat Advisory until 8 PM EDT Thursday for NYZ003>005-013-014. MARINE...None. && $$ SYNOPSIS...Thomas NEAR TERM...Apffel/Thomas SHORT TERM...TMA LONG TERM...JM AVIATION...Apffel/Thomas MARINE...Thomas CLIMATE...Thomas