Saturday, June 27, 2015

Dramatic Pattern Change Brings Fall-Like Storm To the Northeast; South Catches a Break

Linda Lam
Published: June 26,2015

A fall-like storm is setting up for parts of the East this weekend, and it'll have people in the region wondering if it's the end of June or the beginning of October. The forecast is so out of season, meteorologists in Boston are warning it'll be downright "awful."
The same pattern change will also move into the Southeast, ushering in rather pleasant changes after the last 7 to 10 days of uncomfortable and record-breaking heat.
So what's causing the dramatic change? An area of low pressure will move through the Midwest and Northeast, bringing the threat of flooding and gusty winds. Temperatures will also cool closer to average in the South and Mid-Atlantic, while falling up to 20 degrees below average in parts of the Northeast and Midwest.
You can blame the change on the jet stream, which is taking a sharp southward dive over the East, squashing the eastern half of the area of high pressure that has been in place over the South. This will in turn squash the heat wave, leading to cooler conditions.
At the same time as the southward dip in the jet stream slides over the East, the jet stream will lift northward over the Northwest, bringing a record-smashing heat wave to that region.
(MORE: Western Heat Wave May Break June Records)
Here's a layout of how the fall-like storm will impact the region.

Fall-like Weekend


Flood Watches and Warnings

Current Radar






























A windswept, soaking rain is on tap for the first full weekend of summer due to a setup more reminscent of fall.
The incoming southward dip in the jet stream and a strengthening area of low pressure will tap plentiful moisture across the East through the weekend, triggering numerous showers and thunderstorms.
Saturday into early Sunday looks especially wet in the Northeast, with locally heavy rainfall. Showers will linger through Sunday in portions of the region.
Widespread rainfall totals of 1 to 3 inches are expected with some areas seeing more than 3 inches. The heavy rainfall will bring the risk of flooding, and flood and flash flood watches have been posted for portions of the interior Northeast and Midwest.
(MAPS: Daily Forecast)
The rain has pushed Fort Wayne, Indiana, to an all-time record. Downpours Saturday morning not only prompted a flash flood warning for the city, but they also pushed the city's month-to-date rainfall total to 11.56 inches. This sets a new record for the wettest month on record in Fort Wayne, beating the 11.00 inches recorded in July 1986.
Severe thunderstorms are possible Saturday from Pennsylvania and Virginia southward to the Carolinas and Gulf Coast.
The surface low-pressure system will also produce gusty winds in parts of the region, particularly near coastal areas where winds will blow onshore for a time as the low moves through. Gusts up to 35 mph are possible along the immediate coast.

Rainfall Forecast
It will also be windy in the eastern Great Lakes with near gale force winds possible on Lake Erie. The National Weather Service in Buffalo noted that this "low will eventually deepen to nearly 995 [millibars], which is rather unusual for this time of year. In fact, this feature has an occurrence interval of about five to ten years (for late June)."
Tom Niziol, winter weather expert at The Weather Channel, also commented on how unusual this low pressure system is for late June and that if northeast gales do occur on Lake Erie this weekend, it will be pretty rare for this time of year. Niziol said it's important to note because recreational boating is kicking into high gear now on the lake.
In addition to the rain and wind, temperatures will be cool.
(MAPS: Weekly Planner)
New York climbed to 89 degrees on Tuesday, but high temperatures will drop into the 70s through the weekend.
Boston has been fairly cool for June with the average high temperature more than two degrees cooler than average. Highs have only reached 80 degrees seven times this June -- the average number of 80 degrees days in June is 11. Below-average temperatures are expected to dominate beginning late this week with highs only in the 60s through the weekend. Average highs in Boston are near 80 degrees for the end of June.

Forecast Next 3 Days














The National Weather Service weather forecast office in Boston noted in a forecast discussion earlier this week that, "Overall this is an atypical pattern for the beginning of summer. Looks just awful. Overall unseasonable with onshore east/northeast winds. Periods of wet weather at times."
(FORECAST: Newark, New Jersey | Hartford, Connecticut | Indianapolis)
High temperatures may not even reach 60 degrees in Buffalo, New York, and Bangor, Maine, on Sunday. Both locations see average highs around 60 degrees in early-to-mid October.
Temperatures have also been cooler than average in the Midwest, including Chicago, where highs will stay below 80 degrees into part of next week (average highs should be in the mid-80s). Lows will even drop into the 50s the next couple of days.
A noticeable temperature drop will take place in St. Louis as well. Thursday's actual high of 95 degrees was followed by a high of 83 Friday; even with sunshine, Saturday will only reach the upper 70s along with lower humidity.

Southeast Relief

Much of the Southeast has been baking under a strong upper-level ridge of high pressure for more than a week. This has brought a stretch of hazy, hot and humid days.
(MORE: Sweltering Stretch of Record Heat in the Southeast)
Heading into this weekend, high pressure will weaken as that southward dip in the jet stream moves into the East and a cold front moves into the Southeast. This will allow temperatures to return to closer to where they are expected to be for this time of year – much more comfortable than the last week or so.
Instead of highs in the mid-to-upper 90s -- which is a good 5 to 15 degrees warmer than average -- highs may top out in the 80s, which is a smidge below late-June averages. Some cities might even only reach into the 70s.
(FORECAST: Nashville | Charlotte, North Carolina | Birmingham, Alabama)

Forecast Highs in the Southeast














Low temperatures will also be slightly cooler, with overnight highs dropping into the 60s, which should feel downright refreshing after the recent torrid heat.
Dew points will also drop to significantly more comfortable levels. Instead of dew points in the 70s, which have been the norm lately, by Sunday dew points will read in the 50s, with even a few 40s possible. This will make it feel much less humid.
Atlanta has reached 90 degrees 11 out of the last 12 days with the mercury rising as high as 95 degrees. This weekend's highs are expected to be in the low to mid-80s, which will undoubtedly feel refreshing.
Raleigh, North Carolina, has also seen a very warm June with the average temperature more than 3 degrees above average. The thermometer even reached 100 degrees on June 16, setting a new record for the date. Air conditioners will get a little break this weekend with highs in the 80s.
(MAPS: 10-Day Forecast)
Charleston, South Carolina, experienced 10 consecutive days of temperatures reaching at or above 95 degrees. Numerous record warm low temperatures have been set as well over the last few days. This weekend highs will be in the 80s or low 90s and lows will drop back into the lower 70s.
MORE: Summer Solstice (PHOTOS)

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