Rutgers Weather and Climate Monitoring and Weather Forecasting System
Dr. David A. Robinson and Dr. Richard H. Dunk
Program Justification
31 May 2002
4-6 March 2001: “The Storm That Wasn’t”
The 4-6 March 2001 case study documents clearly show New Jersey as the area
expected to receive up to two feet of snowfall, according to the NCEP model forecast
discussion and the ETA model output, as of 3 March 2001. (Figs. 1 and 5)
A heavy snowstorm was expected with over 18 inches of snow throughout New Jersey
according to existing NWS models. (Figs. 5 and 6) The actual snowfall totals ranged
from measurable snow east of Philadelphia to 4.5 inches at New Brunswick to 6 inches
at Newark Airport to 11 inches at Wantage. The NJWxNet was not operational for the
4-6 March 2001 event.
This case serves to highlight the potential of using a higher-resolution model specifically
configured for the wide range of extreme weather that affects the New Jersey area.
RAMS was initialized with the same dataset as the ETA model, thus it shared the same
trend to overestimate the precipitation for the New Jersey area (Fig. 3). RAMS was
configured at the time for local land-based storm systems, making it more difficult to
accurately portray this ocean-based storm. However RAMS forecast significantly less
precipitation and ended the precipitation period earlier than the ETA forecast. (Figs. 2,
3, and 5) RAMS also correctly located the rain/snow line about 40 miles south of New
York City, whereas the ETA model maintained a snowfall event throughout the state.
(Fig. 4)
The 4-6 March 2001 case presents evidence of the higher-resolution RAMS model
providing a more accurate forecast than the ETA model for the location and severity of
the event. NWS forecasters verified the ETA model inaccuracy by the conclusion of the
event. (Fig. 7) RAMS may have recognized the “non-event” more accurately if initiated
using NJWxNet data and configured more specifically for the NJ region to account for
storms originating over the Atlantic Ocean.
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Rutgers Weather and Climate Monitoring and Weather Forecasting System
Dr. David A. Robinson and Dr. Richard H. Dunk
Program Justification
31 May 2002
Figures
Figure 1: This model forecast discussion from the National Center for Environmental
Prediction (NCEP) the afternoon of 2 Mar 2001 highlights the confidence of experienced
meteorologists in the likelihood of a historic snowstorm for the Mid-Atlantic region:
EXTENDED FORECAST DISCUSSION FOR 05 THRU 09 MAR 2001
HYDROMETEOROLOGICAL PREDICTION CENTER...NCEP...NWS...WASHINGTON
DC
3:38 PM EST FRI MAR 02 2001...FINAL VERSION.
POTENTIALLY SERIOUS E COAST STORM STARTING LATE ON DAY 3 (SUN).
THREAT OF HEAVY SNOW AND STRONG COASTAL WINDS CONTINUES FOR THE
MID-ATLANTIC..
...MODEL OVERVIEW AND DISCUSSION...
WE NOW HAVE HIGHER CERTAINTY THAT THERE WILL INDEED BE THE
DEVELOPMENT OF A MAJOR STORM ALONG THE EAST COAST...MAYBE EVEN
A BLIZZARD...IN THE DAY 2-3 PERIOD.
...
THE LATENT HEAT RELEASE OF HEAVY PCPN...COUPLED WITH DESTABILIZATION AS VERY COLD TEMPS ALOFT REACH THE MID ATLANTIC
COAST...COULD GENERATE A VERY POWERFUL STORM SUN NIGHT INTO TUE
FOR THE MID ATLANTIC AND SOUTHERN NEW ENGLAND AREAS. WE FEEL
THAT THE AVN SCENARIO IS BASICALLY CORRECT. EAST COAST...WATCH
OUT!
...
...EAST COAST STATES...
USING THE AVN AS OUR MAIN TOOL...WE LOOK FOR HEAVY SNOW SUN NIGHT
INTO MON OVER THE MID ATLANTIC AND SOUTHERN NEW ENGLAND COASTS.
THERE MAY BE BEACH EROSION AND COASTAL FLOODING...ALONG WITH
WINDS EXCEEDING GALE FORCE ALONG THE IMMEDIATE COAST. FARTHER
INLAND..MODERATE TO HEAVY SNOW AND BLOWING SNOW FROM VA THRU
THE SOUTHERN HALF OF NEW ENGLAND. LOW WIND CHILLS WITH TEMPS
GENERALLY IN THE HIGH TEENS TO MID 20'S. THERE COULD EVEN BE
THUNDERSNOW.
SNOW ACCUMULATIONS MAY EXCEED A FOOT FROM
NORTHERN AND CENTRAL VIRGINIA NORTHEASTWARD THRU THE MAJOR
METROPOLITAN AREAS. THE AVN HAS TARGETED NJ AS AN AREA WHERE
AS MUCH AS TWO FEET COULD FALL.
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Rutgers Weather and Climate Monitoring and Weather Forecasting System
Dr. David A. Robinson and Dr. Richard H. Dunk
Program Justification
31 May 2002
Figures
Figure 2: 48-hr ETA 12-hr total precipitation forecast for 7am on 5 March 2001
Figure 3: 36-hr RAMS 12-hr total precipitation forecast for 7am on 5 March 2001, with
maximum map values approaching 1 inch of liquid equivalent precipitation. Note the
smaller extent of the precipitation versus the ETA map in the figure above.
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Rutgers Weather and Climate Monitoring and Weather Forecasting System
Dr. David A. Robinson and Dr. Richard H. Dunk
Program Justification
31 May 2002
Figures
Figure 4: 36-hr RAMS 12-hr total forecast for 7am on 5 March 2001 for a) liquid
precipitation and b) frozen precipitation with red approaching one inch of liquid
equivalent precipitation. Note the accuracy of the rain/snow line.
Figure 5: 56- and 60-hr ETA 6-hr total precipitation forecasts for 1pm and 7pm on 5
March 2001. Most of this “wraparound” precipitation was not observed, as highlighted
in the NWS discussion in the last figure.
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Rutgers Weather and Climate Monitoring and Weather Forecasting System
Dr. David A. Robinson and Dr. Richard H. Dunk
Program Justification
31 May 2002
Figures
Figure 6: a) 7pm 2 March 2001 RAMS event total precipitation and b) 7pm 3 March 2001
RAMS event total precipitation. Note the forecast time period for a) ends at 7pm 5
March 2001, and the majority of the precipitation in b) occurred between 7am 5 March
and 7pm 6 March. Note the white color equates to roughly two inches of liquid
equivalent precipitation. This figure highlights the early trend for RAMS to keep
precipitation totals less than other models.
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Rutgers Weather and Climate Monitoring and Weather Forecasting System
Dr. David A. Robinson and Dr. Richard H. Dunk
Program Justification
31 May 2002
Figures
Figure 7: 5 March 2001 discussion that summarized the inaccurate model output used
for the NJ area.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
900 PM EST MON MAR 5 2001
AVN BY FAR HAS BEEN THE MOST CONSISTENT MODEL WITH THIS EVENT. WE
OBVIOUSLY UNDERESTIMATED THE AMOUNT OF MELTING THAT OCCURRED
ON THE FRONT END AND THE AMOUNT OF WARM AIR ALOFT THAT CHANGED
THE SNOW TO SLEET. E.G 1 INCH OF SNOW/SLEET AROUND PHI HAD ABOUT .7 - .8
LIQUID EQUIVALENT DOWN HERE (AT MOUNT HOLLY). IF IT WAS JANUARY, 8-10
INCHES COULD HAVE FALLEN EASILY.
ON THE BACK END THE SURFACE LOW HAS INTENSIFIED AND DEVELOPED
TOO FAR NE TO BRING THE HEAVIER PRECIPITATION INTO OUR REGION. AVN
HAD MORE OF A HINT THAN THE ETA. ALSO THE DAYS ARE GONE IN WHICH THE
MODELS
ALWAYS
UNDERFORECAST
THE
INTENSIFICATION
OF
LOWS...SOMETIMES THEY BOOM THEM TOO QUICKLY (12/30 COMES TO MIND)
AND THIS CAN WREAK HAVOC WITH SNOW SITUATIONS. ALL IN THE ALL NOT
A GOOD DAY TO BE A METEOROLOGIST IN PHL...THAT ROOT CANAL IS
STARTING TO LOOK BETTER ALL THE TIME.
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