####018008352#### FXUS61 KBUF 031612 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 1212 PM EDT Fri May 3 2024 .SYNOPSIS... High pressure will continue to slide east into New England today supporting mainly dry weather through much of the day. A warm front will move northeast near the Saint Lawrence Valley this afternoon supporting a surge in warm air, allowing temperatures to soar well above average today. A pair of slow moving cold fronts will then pass across the area tonight through Sunday supporting a couple of rounds of showers and possible a few rumbles of thunder. High pressure then returns Monday, allowing for a dry start to the new work week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Surface high pressure will slide east toward the New England coast today, all the while the upper level ridge axis passes across the area. Additionally, a warm front will push northeast to near the Saint Lawrence Valley this afternoon. Overall this will support warm air advection today, causing temperatures to surge into the mid to upper 70s across the vast majority of the region with a few low 80s possible across far WNY and the traditional warmer spots of the Genesee Valley. Local lake breeze circulations will develop this afternoon making areas along and near the lakeshores cooler, particularly the southcentral and southwestern Lake Ontario shoreline and well along and just inland of Lake Erie. With the high exiting the region through much of today, expect the vast majority of the day to be on the dry side. However, as the aforementioned upper level ridge axis drifts east across the eastern half of the state, southwesterly flow will advect in deeper moisture this afternoon through evening. Eventually by late Friday a cold front will interact with the increasing moisture, and in combination of diurnal heating a few scattered showers and thunderstorms may result. The best focus will lie along the lake breeze boundary inland from Lake Erie. The cold front will then gradually pass across Lake Erie tonight before stalling across Western New York by Saturday morning. This will support showers and thunderstorms to continue to spread across WNY throughout the night. Expect a mild night Friday with lows ranging in the 50s, with the warmer readings occuring along the Lake Erie shoreline. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... A mid level ridge axis will move from NY/PA Saturday morning to off the east coast by Sunday afternoon. A few weak mid level shortwaves will move east into the ridge position and weaken with time. Despite the presence of a ridge aloft, the weekend will be unsettled as a slow moving low level trough and associated plume of deep moisture drifts across the eastern US beneath the mid level ridge. Model guidance has shown some run to run variability with respect to timing of the most organized rain. The general trend since yesterday has been to decrease rain potential on Saturday (especially in the afternoon) while increasing rain chances Sunday. Saturday, a mid level shortwave will move across the eastern Great Lakes and weaken as it encounters the persistent ridge over NY/PA. A weak surface trough and associated area of low level moisture convergence will move across the area in the morning and provide some focus for a few areas of showers and possibly an isolated thunderstorm or two, with the best coverage likely found across Western NY. This trough largely washes out by the afternoon, and ascent and moisture temporarily fade across the eastern Great Lakes. While there may still be a few spotty showers, Saturday afternoon and evening should feature plenty of rain free time. Saturday night will start with only spotty coverage of showers and plenty of rain free areas during the evening. Another mid level shortwave will then move from the Ohio Valley into NY/PA later Saturday night through Sunday, bringing renewed ascent. A plume of deeper moisture will be advected northward into the area as low/mid level SSW flow increases in response to a digging trough over the upper Great Lakes. The increase in forcing and moisture will allow for a commensurate increase in rain coverage from southwest to northeast late Saturday night through Sunday across the region. There may be just enough instability to support some isolated weak thunder. The mid and low level trough axis will gradually move east into New England later Sunday and Sunday night, with rain tapering off from west to east. && .LONG TERM /MONDAY THROUGH FRIDAY/... Surface high pressure over northwest Ontario will ridge southeastward into the Great Lakes Monday, with an associated bubble of dry air bringing a return to dry weather. The dry weather will last into at least Tuesday morning. Model guidance begins to show some spread by Tuesday afternoon with the arrival of the next system. The GFS and GEFS ensemble mean continues to be on the fast side of the guidance envelope, while the ECMWF and GEM are slower. For now kept some chance POPS for Tuesday afternoon, but if the slower guidance verifies Tuesday will end up being dry. Wednesday through Thursday an expansive mid level low will gradually move east across the north central US. A series of mid level shortwaves will eject out of this system and move east across the Ohio Valley and eastern Great Lakes, with each feature bringing ascent and deeper moisture to the region. This will produce occasional rounds of showers and possibly a few thunderstorms for mid to late week next week. Temperatures will continue to run above average through all of next week. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... A combination of exiting high pressure to the east into New England today and a warm front pushing into the Saint Lawrence Valley this afternoon will continue to support VFR flight conditions. Expect at least some thickening mid and upper level cloud decks ahead a weakening cold front slowly approaching from the west, especially across western NY. Despite the increasing cloud cover, VFR conditions will persist. The weakening front will slowly move toward the area this afternoon, with a low chance for a few showers and possibly a rumble of thunder across far western NY late this afternoon into the evening with VFR conditions remaining intact. Showers become likely across western NY tonight, with just a chance of showers from the Finger Lakes east. A few thunder storms will also be possible, especially across western NY. Flight conditions will slowly deteriorate through the overnight with MVFR/higher terrain IFR CIGS possible by late in the TAF period for KBUF/KIAG and KJHW respectively, mainly across western NY...with VFR/low VFR from KROC to KART. Outlook... Saturday...MVFR to VFR with showers likely and possible thunderstorms. Sunday...Morning showers, then a chance of afternoon showers, otherwise mainly VFR. Monday...VFR. Tuesday...Mainly VFR. Chance of showers and thunderstorms. && .MARINE... Mainly weak pressure gradients are expected to persist into this weekend across the lower Great Lakes supporting winds to generally remain below 15 knots. Expect this to bring some choppy waters at times, however conditions will remain below headline criteria, especially with an offshore flow developing tonight then persisting through the weekend, keeping the highest waves over Canadian waters for Saturday and Sunday. While quiet weather continues for the end of the work week, a few showers and thunderstorms will be possible tonight through Sunday. High pressure will build across the area for the start of the new work week providing mainly gentle breezes with no more than some light chop expected through Tuesday. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...JM NEAR TERM...EAJ/JM SHORT TERM...Hitchcock LONG TERM...Hitchcock AVIATION...JM MARINE...JM ####018005076#### FXUS66 KSGX 031614 AFDSGX Area Forecast Discussion National Weather Service San Diego CA 914 AM PDT Fri May 3 2024 .SYNOPSIS... This weekend expect cloudy and cool conditions with gusty winds in the mountains and deserts and periods of showers in and west of the mountains. Southwest to west winds will increase in strength through the day Saturday, peaking Saturday night into early Sunday. The best chances for showers will also be Saturday night into early Sunday. Dry and warmer conditions expected for next week. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... Visible satellite at 9 AM was showing low clouds from the ocean to the coastal mountain slopes. Areas of light drizzle have been reported, mostly in the valleys. Areas of drizzle will diminish through the morning, with very slow clearing of the cloud deck this morning. By this afternoon, the valleys should be seeing some sunshine, with low confidence in complete clearing at the coast and beaches. A low pressure system is on track to move inland through California on Saturday night and dig into the Great Basin on Sunday. This system will bring cooler, cloudier, windier (in the mountains and deserts), and wetter conditions (in and west of the mountains) to Southern California this weekend. Southwest to west winds will begin to increase Saturday afternoon, peaking in strength Saturday night into Sunday, gradually diminishing into Sunday night. Winds will be strongest on the desert mountain slopes, through passes, and into portions of the deserts. Peak gusts of 55 to 65 mph expected. Isolated gusts to 75 mph are possible in wind prone locations on the desert foothills of the San Bernardino mountains late Saturday night. Winds will gradually weaken into Sunday night. For much of next week, a broad troughing pattern over the United States will enhanced the onshore pressure gradient, bringing periods of breezy winds to the mountains and deserts each afternoon and evening. The best chance for showers is late Saturday night into Sunday morning. Coverage will be scattered with mostly light amounts expected. A few hundredths to a tenth of an inch of rain are expected for the coast and valleys. One-quarter to locally one-half inch expected on the coastal slopes of the mountains with the greater amounts most likely on the coastal slopes of the San Bernardino County mountains. A trace of snow is expected above 7000 ft. Dry conditions are expected by Sunday afternoon. Highs Saturday are expected to be 3 to 5 degrees below average for the coast and valleys, and near average for the deserts. Sunday will be even cooler, especially for inland areas with highs 10 to 15, locally up to 20 degrees below average for the valleys, mountains, and deserts. Warming conditions expected on Monday, with highs as much as 10 to 15 degrees warmer for the mountains and High Desert. Much slower warming for Tuesday through Thursday with Thursday high temperatures still a few degrees below average. && .AVIATION... 031530Z...Coasts/Valleys...Low clouds based at 1000-1800 feet MSL with pockets of -DZ lowering cigs to 800 feet and inland vis 2-5SM. Foothills obscured, but lifting and clearing. The clearing progression inland to coast should accelerate after 17Z, but with limited or no clearing in coastal areas. Low clouds will spread inland again this evening with slightly higher bases and push into foothills again by 13Z Saturday. Scatter out Saturday will be slow and gradual again Saturday morning. Otherwise...Clear skies with unrestricted VIS will continue through tonight, with increasing high clouds above 15000 feet MSL Saturday. && .MARINE... No hazardous marine conditions are expected through Saturday morning. Gusty west to northwest winds late Saturday through Sunday evening are likely to generate hazardous boating conditions, especially in the outer waters (30-60 NM from the coast). Current projections for strongest winds are on Sunday when gusts could be 25- 30 knots near San Clemente Island with a few gusts 20-25 knots near the coast. No additional hazardous marine conditions are expected Monday and beyond. && .SKYWARN... Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...Wind Advisory from noon Saturday to 8 PM PDT Sunday for Apple and Lucerne Valleys-San Bernardino County Mountains-San Gorgonio Pass Near Banning. Wind Advisory from 3 PM Saturday to 8 PM PDT Sunday for Coachella Valley-Riverside County Mountains-San Diego County Deserts-San Diego County Mountains. PZ...None. && $$ PUBLIC...CO AVIATION/MARINE...MM