Weekend Storm Verification

Forecast period: Saturday Dec. 15 (afternoon) through Monday Dec. 17 (afternoon)
Location: Delaware Valley
Verification Station: KPHL

Saturday Afternoon

Prediction: Clouds start to move in and temperatures drop. Hi: 38 POP: 10% PTYPE: Rain

Actual: Mostly Cloudy all day, Overcast by 5:00pm; Hi: 37; No Precip until night

Saturday Evening/Overnight

Prediction: Temperatures fluctuate, dropping for a time then rising. Under overcast skies, light flurries may fall (though not likely) before giving way to sleet and freezing rain overnight. Lo: 30 POP: 80% PTYPE: Freezing Rain

Actual: Overcast all night, Light Freezing rain to plain light rain (total: 0.86 inches from midnight through 6:00am); temp dropped to 32 before going back up to 40 by 6:00am; Lo: 32

Sunday

Prediction: Temps will rise during the day, with a good amount of rain falling. This will be steady most of the time during the day. Hi: 42 POP: 100% PTYPE: Rain

Actual: Rain tapered off by early afternoon, with no more measurable precip after 3 pm (totaling a mere 0.15 inches); Hi: 44

Sunday Night/Overnight

Prediction: Cold air will rush in as the new low, which develops over D.C. around Sunday morning, pushes northward. This cold air will push all the way out to the coast by Sunday evening, turning any more falling precip to snow. This also has the potential to freeze over any rain, leading to black ice on the roads overnight and into Monday. Lo: 24, maybe even lower POP: 60% PTYPE: Sleet to Snow

Actual: Cold air did rush with a LOT of wind (top gust at KPHL was 52 MPH, between 6 and 7 pm), however, there was NO precip whatsoever. Lo: 32 (Wind Chill low was 18)

Monday Morning

Prediction: Precip is done with and skies clear up, leading to cooler temps. Travel conditions potentially hazardous in the morning, especially before sun rise and throughout the morning on back roads. Hi: 34 POP: 10% PTYPE: Snow

Actual: No Precip; Skies had few or scattered clouds all day, with winds around 20 MPH all day; Hi: 37

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Remarks: I was off on the precip timing, with most of it occurring in the early morning hours of Sunday, before dawn. I was also wrong in the fact that we had NO precip Sunday evening, when I gave a POP of 60%. As far as temperatures go, I was within 2-3 degrees each period with the exception of (again) Sunday night. Hmm… maybe it’s a wanting-to-get-off Monday effect on me, despite me being out of school for break and without a job yet… haha. Overall, I would give myself a grade of C for the forecast. I was CLOSE on temps (forecast was made Thursday night, FYI), and had all the right PTYPE’s, but my timing was off with when the majority of the precip would come. Also, I never mentioned wind in any forecast, which was a fault of mine. Oh well- Live and Learn!Temp. accuracy (+ means I was over, – means under): +1, -2, -2, -2, -8, -3

From this, I can learn that my forecasts were, for the majority, always too low.

That’s all for now!