THUNDERSTORM UPDATE

[su_note note_color=”#ffffff”]Updated Fri 05:14 PM — Here’s current radar at 5:09 PM.  Showers usually don’t develop in the exact position predicted by the models.

Radar Friday 5:09 PM (courtesy of WeatherTap.com)

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Last night’s models continue with the idea that scattered thunderstorms are possible Friday afternoon and early evening. They will be scattered, but more widespread than my earlier forecast had suggested from last night.

Some possibility of very widely scattered (isolated) thunderstorms as early as 2 PM.  A bit more widespread between 5 PM and 10 PM.  Not everyone will get a thunderstorm.

(“Predicting thunderstorms is like trying to guess which spot in a saucepan is going to form the first bubble when heating water to a boil”.)

Here’s another approach to predicting thunderstorms:  Upward Vertical Velocity (dark circles) combined with available energy (CAPE).  The exact location of these areas is never exactly as shown.

HIREF (experimental) model 7PM CAPE with Vertical Velocity   (Click on image for a larger view.)

FRIDAY — NOT MUCH SHOWER ACTIVITY?

[su_note note_color=”#ffffff”]Updated Thurs 10:45 PM— Tonight’s HIRESW model just became available.  It shows significant moisture convergence and vertical dynamics at 1 PM and again at 5 PM. This suggests showers/thunderstorms are possible around Philadelphia. The HIRESW has been doing well.  This may negate the forecast below. I guess we’ll find out.

HIRESW model  5 PM moisture convergence (red) and vertical velocity (black)

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A broad upper cyclonic flow will replace the closed upper low on Friday. An area of moisture and clouds moves through mid day Friday.

So mostly sunny with a period of cloudiness  Most areas will not have any showers on Friday. High 83.9° sd 1.8°.   Dew points in the mid 60s.

Right now, the weekend is looking similar— increasingly warm and more humid.  Most areas near Philadelphia won’t have any showers.