June 18, 2013: Storms Today, Seasonable Ending To Week

Forecast Highlights:

A cold front that produced isolated thunderstorms yesterday continues to track closer to the area, with widespread showers and thunderstorms expected this afternoon. Behind the cold front, mostly sunny skies will return for the second half of the week with temperatures slightly below average, mostly in the mid 70s-low 80s. A gradual warming trend will continue through early next week, when a heat surge is possible.

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Note: The 5-day outlook will be updated early this afternoon, and storm summaries from the last 2 storms will be added within the next 2 days.


Today's Outlook: Showers, Storms

As of this morning, the cold front was located over northern PA and SE NY, slowly moving to the southeast.  The regional radar posted above shows an area of rain located in the southwestern parts of the region. This area of rain will continue to extend ENE into the central-southern Mid Atlantic region, mostly south of PA/NJ, in the late morning and afternoon hours. Meanwhile, partly cloudy skies are expected to continue in the area until the early afternoon with temperatures warming up into the upper 70s to low 80s. By the early afternoon hours, scattered thunderstorms will form over NE PA and SE NY, slowly tracking southeast and affecting the area mainly after 4-6 PM. Most storms are expected to be non-severe, but are still capable of producing heavy rainfall and gusty winds. Storms will spread into Long Island this evening, with the rain then gradually ending across the area.

Storm updates will be posted after 2-3 PM, both on the blog and on Twitter.


Weds - Saturday: Dry, Slightly Cooler Than Average

As the cold front moves out and troughing returns into the region, a high pressure will build in, providing mostly sunny skies for Wednesday through Saturday. Temperatures will initially start out slightly cooler than average, peaking in the mid to upper 70s with a light north wind. Thursday will continue the warming trend, with highs in the upper 70s to near 80 along with a light and variable wind. As the high pressure shifts south, a SW flow will develop for Friday and Saturday with the gradual warm trend continuing, with highs expected to reach the upper 70s to mid 80s on both days.


Sunday - Next Week: Heat Possible

Ridging over the central US will continue to gradually shift east, with a W-SW flow developing aloft by the late weekend into next week. This setup will support a warm air mass in the central US gradually shifting into the region, with 850mb temperatures reaching the 15-20C range, supporting at least a brief surge of heat with temperatures near/over 90 degrees possible. As this is still at least a week away, there is uncertainty regarding the setup, including the timing, strength and duration of the warm air mass. The GFS and DGEX show a several day heat wave beginning on the 23rd with temperatures in the low-mid 90s for almost a week. The 0z ECM, however, keeps temperatures cooler than average through the 24th, followed by a brief 2-day warmth surge and another cool down. Should the ECM scenario verify, storms may be possible on Sunday and/or Monday. The current outlook is for a risk of scattered storms on Sunday and possibly Monday, followed by warm temperatures, possibly near/above 90 degrees, although the outlook is subject to some changes. Stay tuned for more information on next week's outlook.


Tropics Update: The second tropical depression of this year's Atlantic hurricane season formed yesterday in the western Caribbean, and has since made landfall in Belize. The tropical depression is currently likely to remain below tropical storm intensity as it tracks into Mexico, and will stay well to the south of the US. Otherwise, there appear to be no additional potential tropical cyclones in the Atlantic basin for the next week.