December 31, 2000
The final storm of the century is now history and left parts of our area with a decent amount of snow. For our area (central Delaware County) we received around 5.5 inches of snow. That falls right in line with our last minute thinking yesterday of 4-7 inches. As you can see, a variety of totals fell across the region. Here are a few select locations:
SUSSEX (SUSSEX COUNTY, NJ):25"
MADISON (MORRIS COUNTY, NJ):16"
FLEMINGTON (HUNTERDON COUNTY, NJ):13"
NORTH PLAINFIELD (SOMERSET COUNTY, NJ):12"
YARDVILLE (MERCER COUNTY, NJ):12"
MARLBORO (MONMOUTH COUNTY, NJ):9.3"
ALLENTOWN (LEHIGH COUNTY, PA):6"
READING (BERKS COUNTY, PA):2.2"
PERKASIE (BUCKS COUNTY, PA):12"
NORRISTOWN (MONTGOMERY COUNTY PA):7"
GLENMOORE (CHESTER COUNTY, PA):1"
PHILA INTL AIRPORT (PHILADELPHIA COUNTY, PA):9"
So, you can see why this was such a tough storm to predict as far as totals. There was a very tight gradient between heavy snow and virtually nothing. As stated above, we received generally from 5-6 inches in central Delaware County, PA, but just 10 miles west into Chester County, they received less than an inch. On the other hand, about 10 miles east into Philadelphia County, they recorded amounts from 9-10".
Now, why did the storm develop farther north and east than progged and move so quickly north? Well, simply stated, the upper low over the Ohio Valley did not dig quite as far south as guidance was indicating. That in turn caused the system to develop farther North, closer to the vicinity of Cape Hatteras latitude line as opposed to the NC/SC border.
So why didn't we, or any of the NWS forecast offices in the northeast pick up on this until around 1AM Saturday? At 5PM, there were hints from guidance that the storm may be shifted *slightly* farther east. That was not a huge deal at that time as guidance usually bounces around 25 miles in either direction at that period before the storm develops. However, perhaps this would have been picked up better on guidance and Northeast NWS stations earlier last night if it weren't for a lack of communication on the part of NCEP (National Centers for Environmental Prediction). Last evening, a jet was sent down into the south to retrieve upper air data on this developing storm. Well, the jet never returned to base with that data and rather then sending out a notice statement to local offices, they just let it pass. They did, however, discuss the situation in their Model Diagnostic Discussion last evening, but this is often overlooked when stations write their AFD's. Upon looking at several area forecast discussions across the Northeast issued in the early morning hours, not one station knew of this error. Perhaps if a statement by NCEP was issued directly to each office, there would have been more knowledge of what was actually transpiring as far as storm development. This is not to say this is the reason why areas like DC and BWI still called for significant snow through 4AM, only to receive sunshine on Saturday, but this would have likely opened the eyes of many stations that were unaware of the error in initialization. Regardless if this was the cause or not for many stations to continue their call for significant amounts of snow even though current obs at 6Z last night showed something totally awry, it definitely show me a lack of coordination between NCEP and areawide offices in not letting the stations know first hand there was an error. Yes, they post a Diagnostic Discussion, but many stations overlook it. Perhaps something to be looked at in the future.
What went wrong with our forecast? The preliminary amounts posted here within 24 hours of the storm were well over what we actually got. What went right with our forecasts? The storm *did* hit us as was called several days in advance. As soon as things were not looking correct upon development, the amounts were updated to 4-7" in Delaware County and verified. As was mentioned in several discussions, any slight shift would have meant drastic changes in amounts as there was such a tight gradient between heavy snow and flurries. Think that was well predicted ahead of time as well. So, generally think this thing was predicted fairly well. This may just be a tuneup for what's to come the reast of the winter. It's only December 31 and we already have received close to, if not more than what we saw the entire season last year (where most fell from one storm on January 25th).
What to expect this week: Sunday will be partly sunny and breezy with the high around 30. Can't rule out the chance for a flurry. New Year's Eve night will be clear with a low in the upper teens. New Year's Day will be partly sunny with the high around freezing. Tuesday will be partly to mostly cloudy with a chance for some flurries in response to a system developing well off the North Carolina coast. Flow looks progressive and trough positively tilted, so doesn't appear to be a threat. High in the upper 20s to near 30. Wednesday will be partly cloudy, high around freezing. So a pretty quiet week for weather unless you like cold. Next *chance* for snow would be late in the week. Right now, looks too far east, but that is our best chance at the moment. Have a happy and safe New Year and New Century. Here are a few weather highlights from the 20th Century:
-1900 Galveston Hurricane
-1925 Tri-State Tornado
-1935 Floriday Keys Hurricane
-1938 New England Hurricane
-Blizzard of 1940 (The Armistice Day storm)
-The Dust Bowl
-1969 Hurricane Camille
-The Great Tornado Outbreak of 1974
-The Blizzard of '78
-Hurricane Andrew 1992
-The Storm of the Century/Superstorm 1993
-Blizzard of '96
-Hurricane Floyd 1999
There are *many* others, but these are probably some of the most notable. Have a great holiday.
