North American Mesoscale Model Verification on January 26-27...

By: Zachary Labe , 10:34 PM GMT on January 29, 2011

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The North American Mesoscale Model (NAM) is a high resolution model courtesy of the National Center for Environmental Prediction. Another very common and referenced name for the model is the Weather Research and Forecasting Model (WRF). They are the same model and run out to 84 hours. The purpose of the model is to run a higher resolution determining mesoscale features that often cannot be picked up by the global models due to their larger scale. The NAM can be run on an 80km resolution with a broad view of the United States, or 40km which allows the viewer to zoom in on a localized region to put up on mesoscale features. Also a very high resolution form of the NAM exists using a 12km parametric and can zoom into different states. The model is released four times a day at 0z, 6z, 12z, and 18z. Keep in mind that time is zulu or more commonly known as greenwich mean time.

Computer models are critical to forecasting the weather as they use parametric and other mathematical equations to derive the current and predicted state of the atmosphere using a physical and chemical explanation as the background for the predictions. The NCEP is associated with the National Oceanic Atmospheric Administration (NOAA) to be the developer of these computer models. Each meteorological organization worlwide uses their own developed computer models to serve as a basis for the forecasts. Without computer models, we are not able to derive predictions on the weather greater than 24 hours out.

Like all computer models, the NAM shows all layers of the atmosphere in maps determining positioning and speed of the jet stream, surface precipitation amounts (quantitive precipitation forecast QPF), temperatures throughout the entire core of the atmosphere, convective indices, simulated radars, etc. Due to the higher resolution of the NAM, several problems do exist. It often produces convective elements in many middle latitude cyclones and these are known as convective feedback problems. This is where it developed these unstable regions and often associates them as surface lows causing the surface depiction to be distorted. This was a problem in the recent prediction of the January 26-27 winter storm and will be noted below. Also the NAM has a tendency to produce higher than normal precipitation amounts. I typically find myself cutting totals nearly by 30% as shown on the NAM. Finally the NAM has a bias to overamplify a low pressure and close them off to early particularily on eastern United States cyclogenesis off the coast.

The January 26-27 winter storm featured many model headaches do to some interesting variables. Early on it appeared likely for a low pressure to track up inland along the coastal plain. There was a lacking 50/50 low, unfavorable position of the western trough axis, neutral NAO, natural baroclinicity along the coastline, and stale antecedent cold air mass. This would produce rain along I-95 with heavy snows inland. The 500mb synoptic pattern showed very strong signals for this time of setup with most computer model guidance also in support. The GGEM and ECMWF led the pack with the heavy snows from I-81 on westward. The GFS suffered major problems with varying solutions for each run. But then the computer models began to delay the storm. In fact it was delayed nearly 48-60 hours from the original starting time. This caused a different scenario to unfold. The lacking high pressure to the north was still a problem as the anticyclone zoomed east-northeast, but now a high pressure and associated shortwave out ahead of it allowed sunk east-southeast across the Midwest and western Great Lakes. This acted as a 'kicker' helping to push the cyclonegenesis farther off the coast. This in turn allowed for a colder scenario along with precipitation to occur farther east. Therefore a turn of events allowed for a major I-95 snowstorm with 6in+ totals from Washington DC to Boston. This was very fortunate for snow lovers in that corridor due to pure luck given the poor synoptic setup.

Given the NAM's high resolution, it often overanalyzes prognostics post hour 60. It tends to enhance QPF, overamplify lows, and pick up on mesoscale features that really do not exist. Therefore I typically throw out hours 60-84. It would be a rare event where you would find the NAM 84 hour verifying anywhere close to accurate. But in the near term range, the NAM does an excellent job locating temperature thermals, QPF ranges, and picking up on mesoscale features; coastal fronts, enhanced convection, deformation bands, etc. But in this recent storm, it suffered a plethora of problems and even the 6 and 12 hour surface maps had poor verification especially in the QPF department.

Let us first look at the actual accumulated precipitation totals for the storm.

Given this is a 24 hour accumulated precipitation amount, about .01-.1in of additional precipitation fell south of the Mason-Dixon line in the previous 24 hours.

Here are the preceeding NAM total QPF forecasts...


(January 24; 18z) (January 25; 6z)


(January 25; 12z) (January 25; 18z)


(January 26; 0z) (January 26; 6z)

As you can see, the NAM had a lot of variance with the northwestern sharp precipitation gradients. These tight gradients this year have been caused by the rapid intensification of the coastal lows allowing the heaviest moisture to be confined closer to the center of circulation. Also in this instance, a very cold and dry air mass along with associated cold front was quickly advancing southeast across the Great Lakes and was even picked up on by the 700mb RH charts. This allowed the flow out of the northwest to dry up some moisture for areas more inland.

The NAM simulated radar vs. the forecast QPF did not match up. Often the NAM simulated radar showed the heavier mesoscale bands lining up in northern Maryland and southern Pennsylvania where as it only showed total QPF to be .25in-.5in. In fact looking at total verification, the NAM did very well for its simulated radar.


(Actual NEXRAD National Radar) (6z NAM January 26 Simulated Radar)

The NAM did seem to have a hold on the 500mb map showing the negatively tilted trough producing the coastal low along with the placement of the upper level low and associated shortwave kicker just to the west.


(18z NAM January 24; 500mb) (0z NAM January 26; 500mb)

In general the differences in the 500mb maps were very subtle with just a general strengthening in the closed 500mb low, which verified a tad north of the January 24 18z model run.

The NAM did a very excellent job in identifying mesoscale band using the UUV/700mb RH charts.

(6z NAM January 26; 700mb)

It indentifed the enhanced snow growth over southeastern Pennsylvania up through New Jersey and New York City. The problems with the NAM generally existed in the QPF fields. The model likely suffered a very convective feedback issues in QPF totals. This is why it is important to note other maps than surface maps to help locate the heaviest precipitation. The 700mb map screamed that snow totals would be farther inland with the enhanced deformation band and UUV rates. In general the high resolution models handled this the best with the HRR scoring an amazing victory for QPF along with the ECMWF. The GFS/NAM did a very poor job for QPF, but as noted above QPF does not always tell the story. Sometimes it is important to note other layers of the atmosphere to help make a forecast. This point is why many forecasters missed the boat. Many forecasters (especially broadcoast meteorologists) are drawn to the easy to understand QPF/surface maps, but one has to look at all layers of the atmosphere to make a prediction.

Lower Susquehanna Valley Doppler...

(Courtesy of WGAL)

"Here northeast of Harrisburg 2010-2011 winter statistics"
(Snow Stats)
Current Snow Cover- 0-3in
Monthly Total (November)- Trace
Monthly Total (December)- 0.6in
Monthly Total (January)- 18.90in
Monthly Total (February)- 1.35in
Seasonal Total- 20.85in
Winter Weather Advisories- 7
Winter Storm Warnings- 2
Ice Storm Warnings- 0
Blizzard Warnings- 0
Freezing Rain Advisories- 1
Winter Storm Watches- 2

(Temperature Stats)
Lowest High Temperature- 23.7F
Lowest Low Temperature- -1.7F
Wind Chill Advisories- 0
Wind Chill Warnings- 0

(Snow Storms Stats)
First accumulating snow - December 10 - 0.50in of snow
Clipper light snow - January 7-8 - 2.25in then another 1in of snow
Double Barrel Low - January 11 - 4.5in of snow
Coastal Low - January 17-17 - 1.8in of snow/sleet
Arctic Front - January 20-21 - 2.1in of snow
Upper level/coastal low - January 26 - 5.75in of snow
Two clippers - January 28-29 - 1.5in of snow

Ice Storm 2011... (Blizzard92)
.4-.5in of freezing rain
Ice Storm 2011...
Ice Storm 2011... (Blizzard92)
.4-.5in of freezing rain
Ice Storm 2011...
Ice Storm 2011... (Blizzard92)
.4-.5in of freezing rain
Ice Storm 2011...
Ice Storm 2011... (Blizzard92)
.4-.5in of freezing rain
Ice Storm 2011...
Ice Storm 2011... (Blizzard92)
.4-.5in of freezing rain
Ice Storm 2011...
Ice Storm 2011... (Blizzard92)
.4-.5in of freezing rain
Ice Storm 2011...
Ice Storm 2011 (Blizzard92)
Melting begins...
Ice Storm 2011
Ice Storm 2011 (Blizzard92)
Melting begins...
Ice Storm 2011

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Quoting Blizzard92:

Hahaha... somehow I had a feeling they did not work too well.


Now you know why Blizz refused to go to State College and decided Cornell was better suited. hahahaaha
Member Since: January 26, 2007 Posts: 72 Comments: 6259
Quoting Snowlover2010:
Freezing drizzle now in State College. Most of the "heated sidewalks" are already sheets of ice.

Hahaha... somehow I had a feeling they did not work too well.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
Quoting P451:
Icing totals continue to go up for the lower hudson valley, long island, and ct.



Back in 2006 in NJ, Valentines Day Ice Storm, we had so many trees ripped apart by what I think was somewhere around 0.6-0.7" of icing.

So, with these totals forecasted, it'd be wise to start up the fireplaces and keep them going, get your flashlights and candles in order, and water set up.

If you operate off of a well... no power = no water, not even for flushing.

So keep it in mind if you're living in wooded areas where power lines are under continuous threat every inch of the roads from tree limbs.

I would hope everyone already bought food prior to the storm.

Beyond that just hope they are wrong just like they were about the snow.



i believe you have as much water as is in your pipe from the well. that is what someone once told me. I could be wrong. I know you have at least as much as is in your holding tank.
Member Since: January 26, 2007 Posts: 72 Comments: 6259
Freezing Rain Advisory...I don't recall seeing one of these since the snow/ice storm of February 12, 2008. We also had a significant snow/ice storm on February 13-14, 2007 that I believe prompted those warnings. Calling for 0.15-0.25" of icing followed by moderate to heavy rain.
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Freezing drizzle now in State College. Most of the "heated sidewalks" are already sheets of ice.
Member Since: January 7, 2008 Posts: 2 Comments: 1003
Looks like that rain/snow line is creeping north, does anyone think I should be safe from it?

Albany and Boston in total disagreement on snow totals...

Springfield, MA
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Just hit freezing here at the shore. Wind is calm.
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Quoting koldkat:
Hi there - I am in Middlesex County, NJ. We are under an ice storm warning. I have lived here for many years and I don't recall ever seeing this warning. Anyone else from this area? I am new here and this is my first post. This website is great. Thank Matt Drudge


Welcome - I'm on the Monmouth/Ocean border. I remember a warning back in the mid 70's when the area was hit with a very bad ice storm. Lost a lot of trees that year.
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Hi there - I am in Middlesex County, NJ. We are under an ice storm warning. I have lived here for many years and I don't recall ever seeing this warning. Anyone else from this area? I am new here and this is my first post. This website is great. Thank Matt Drudge
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Blizz - What is interesting is how much colder you are running compared to how much warmer we are running along the shore. The ocean allows the cold air to drain off fast and warm air to infiltrate.

Currently 32.4 degrees and overcast.

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Just curious.

How bad is .25" of ice?

.5"?
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Hey Blizz I've heard some meteorologists say that this month will be our "vacation" from the bad winter, but March and April is supposed to be a return to the same pattern we had in January. I was wondering what your thoughts on this were. Is NAO supposed to go back negative later in the month? I only know how to find up to 14 day model runs for the oscillations
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Quoting LivelySnow:


Still trying to learn! Thanks so much! Could get ugly then where I live....nothing but trees! Ugh!

That chart in comment #596 is pretty neat and shows what all of the models predicted the surface temperatures to be versus what is actually happening. As you can see, we are running a tad colder. Here is the link for a bigger picture of the chart...Link
Member Since: December 14, 2007 Posts: 284 Comments: 15112
Quoting Blizzard92:
SilverShipsofAndilar- .25-.5in of freezing rain for the immediate urban areas around Harrisburg increasing up to .75in for more rural areas and those along Blue Mountain on northward. South of the turnpike a general .25-.5in with lesser amounts the farther south one goes towards the Mason-Dixon line.

LivelySnow- The NAM has a higher resolution than the other models are can pick up on cold air damming. All of the other models were significantly too warm already today.


Still trying to learn! Thanks so much! Could get ugly then where I live....nothing but trees! Ugh!
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Quoting Finky:


Blizz,

Is Adams County looking like a mostly rain event or are we still looking some major ice?

Probably around .25in for the immediate Gettysburg area for freezing rain; maybe a tad more.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
600. Finky
Quoting Blizzard92:

While it stay may be a significant ice storm up there, I think sleet accumulations will prevent the maximum ice accretion there.


Blizz,

Is Adams County looking like a mostly rain event or are we still looking some major ice?
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We went from Winter Storm Warning to Winter Weather Advisory to Freezing Rain Advisory.
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Quoting Snowlover2010:


So ya think up towards .75in of freezing rain up here in State College?

While it stay may be a significant ice storm up there, I think sleet accumulations will prevent the maximum ice accretion there.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
Quoting Blizzard92:
SilverShipsofAndilar- .25-.5in of freezing rain for the immediate urban areas around Harrisburg increasing up to .75in for more rural areas and those along Blue Mountain on northward. South of the turnpike a general .25-.5in with lesser amounts the farther south one goes towards the Mason-Dixon line.

LivelySnow- The NAM has a higher resolution than the other models are can pick up on cold air damming. All of the other models were significantly too warm already today.


So ya think up towards .75in of freezing rain up here in State College?
Member Since: January 7, 2008 Posts: 2 Comments: 1003
Member Since: December 14, 2007 Posts: 284 Comments: 15112
SilverShipsofAndilar- .25-.5in of freezing rain for the immediate urban areas around Harrisburg increasing up to .75in for more rural areas and those along Blue Mountain on northward. South of the turnpike a general .25-.5in with lesser amounts the farther south one goes towards the Mason-Dixon line.

LivelySnow- The NAM has a higher resolution than the other models are can pick up on cold air damming. All of the other models were significantly too warm already today.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
Good Discussion on Ice from the NWS Mount Holly:

NOW FOR THE ICE WARNING AREA. THERE ARE STILL SOME MODEL CHANCES OF
SLEET AND POSSIBLY EVEN SOME SNOW AS PRECIPITATION INTENSITY
INCREASES OVERNIGHT FAR NORTH. THIS WOULD BE A WELCOME SIGHT AS
THIS WOULD CUT DOWN ON ICE ACCUMULATIONS. THE CHANCES OF THIS
OCCURRING OUTSIDE OF SUSSEX COUNTY NEW JERSEY AND THE POCONOS GETS
LESS AND THE HIGHEST IMPACT ICE ZONE MAY BE JUST SOUTH OF THIS
REGION. MODEL QPF SUGGESTS UP TO ONE INCH OF ICE COULD ACCUMULATE,
BUT ICE ACCUMULATION IS NOT ONE FOR ONE. SOME OF IT DEPENDS ON
INTENSITY, THE HEAVIER, THE LESS TIME IT HAS TO ACCUMULATE BEFORE
FALLING. TEMPERATURES CLOSE TO FREEZING ARE NOT AS EFFICIENT FOR
ICE ACCRETION. PLUS ONCE THE SUN RISES INDIRECT INSOLATION WILL
TAKE ITS TOLL. TU ABW FOR LWX WITH HELP WITH THIS. NEVERTHELESS
THE CENTER OF THE BELL SHAPED CURVE FOR ICE WILL BE AROUND HALF AN
INCH WITH THE PROBABILITY OF THREE-QUARTERS OF AN INCH OCCURRING
IF NOT MUCH SLEET FALLS. GETTING TO THE PHL NORTHWESTERN SUBURBS
AND CENTRAL NJ, THE TRANSITION TO RAIN ON WEDNESDAY MORNING AND
HIGHER SFC TEMPS SHOULD CUT DOWN ON ICE ACCUMULATIONS SOMEWHAT.
WITH THESE AMOUNTS, POWER OUTAGES COULD EASILY OCCUR IN THE
WARNING AREA.

WHILE NOT INCLUDED IN THE FORECAST ATTM, MODELS BRING THE FORECAST
SHOWALTER INDEX RIGHT AROUND 0C. WE DO NOT MENTION THUNDER IN THE
GRIDS OR FORECAST, BUT AN ISOLATED RUMBLE OR TWO OF THUNDER WOULD
NOT BE A SURPRISE.-- End Changed Discussion --

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Member Since: July 15, 2006 Posts: 174 Comments: 54426
Member Since: July 15, 2006 Posts: 174 Comments: 54426
Quoting Blizzard92:

Yes, some of it runs off and that is true. Given it is night with the loss of solar radiation, that will not help though.


Think of it this way, running water has a tough time freezing so heavy rain has the same properties on wires and trees in that it falls to the ground faster than it can freeze on the surface of objects unlike in a light rain or drizzle environment where it can cling to the object longer.
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Quoting Blizzard92:
18z NAM is scary icy. Just about .8in of all freezing rain here in the Harrisburg area tonight. I hope people are still taking this storm seriously despite a long lull.


hopefully everyone will have flashlights ready. water. i know i will have my wood stove ready to go. i need to read my survival book again
Member Since: January 26, 2007 Posts: 72 Comments: 6259
Quoting Blizzard92:

Yea, the NAM spells bad news for our area. .8in of freezing rain will have major implications especially as we get 35-40mphg gusts after the frontal passage tomorrow.


So, we're going with the NAM, not the gfs?
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Blizz, have you made an official prediction for expected freezing rain amounts?
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Temp is definitely dropping along the shore here. Was 38 now 33.4. The pressure has steadily declined through the day.

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Quoting 717WeatherLover:
Well, off to take a nap before the excitement. Went to the DR while at work this morning thinking the crud that I got from Blizz had turned into a sinus infection. The DR confirmed sinus infection but was more worried about the pneumonia in the lower lobe of my right lung. I think it may be the first time I was ever sent home from work sick.


I caught Blizzitis as well. Cant breath!!!
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Current temp here in West Chester is right around 30F and it's slightly foggy. NAM says we're going to get dumped on with rain by 6am with a QPF of .5 to .75". We are right on the southern ice/rain line I believe--which is good for us but bad for points north. Still, I went out and stocked up on emergency rations (i.e.: beer) just in case. :)
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Well, off to take a nap before the excitement. Went to the DR while at work this morning thinking the crud that I got from Blizz had turned into a sinus infection. The DR confirmed sinus infection but was more worried about the pneumonia in the lower lobe of my right lung. I think it may be the first time I was ever sent home from work sick.
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Does this mean it has trended colder for us in New england as well?
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Winter Storm Warning changed to Ice Storm Warning for Trenton, NJ for hq tenths of an inch frz rn. Mount Holly has been pretty good n efficient so far this season but throwing me for a loop this time. Maps, warnings and forecast wording just havent matbahed up. 4 to 7 tenths solid ice w power outages in warning, trace ice non event in forecast wording. Away from home so I rely on them while at work n school but I have no clue whats going on.
Member Since: December 17, 2009 Posts: 0 Comments: 796
Quoting 717WeatherLover:
There has been talk that heavy rain doesn't equal heavy ice accumulation for freezing rain. Maybe we have that going for us?

Yes, some of it runs off and that is true. Given it is night with the loss of solar radiation, that will not help though.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
There has been talk that heavy rain doesn't equal heavy ice accumulation for freezing rain. Maybe we have that going for us?
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Quoting Blizzard92:
18z NAM is scary icy. Just about .8in of all freezing rain here in the Harrisburg area tonight. I hope people are still taking this storm seriously despite a long lull.


i'm at 29f down here along south mountain. dew is 28f.
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Quoting 717WeatherLover:
The 18Z NAM is looking colder and more like epic ice storm for Central PA. Don't have the text product for actual but looks like about .8" frozen rain for Dauphin/Cumberland.

Yea, the NAM spells bad news for our area. .8in of freezing rain will have major implications especially as we get 35-40mphg gusts after the frontal passage tomorrow.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
The 18Z NAM is looking colder and more like epic ice storm for Central PA. Don't have the text product for actual but looks like about .8" frozen rain for Dauphin/Cumberland.
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18z NAM is scary icy. Just about .8in of all freezing rain here in the Harrisburg area tonight. I hope people are still taking this storm seriously despite a long lull.
Member Since: December 14, 2007 Posts: 284 Comments: 15112
Quoting zotty:
Good Afternoon- 24 degrees in White Plains, NY (20-30mi N of NYC), down from 27 a few hours ago.  I just scraped off a half an inch of ice off of my car.  After clearing the windows and driving around for a bit, I determined I had to clean the ENTIRE car off.  The ice weighed a ton (literally)!  The car handled poorly and had trouble stopping with all the added weight.
 i'd recommend people take the time to clear the whole car, or leave a LOT of room for breaking.
Roads are in reasonably good shape.  A lot of sand has offered traction.  


WOW!! I never even thought of that. By my house its now 21 down from 27 (Roseland, NJ) My high tomorrow is down to 33 from 37 this morning. Forecast is now for about .5 inches of ice. This could get ugly. Especially with the falling temps. Seems like the Low is verrrrrrry slow.
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574. bwi
We don't tend to get flash freezes down here even when strong cold fronts go through. Because of warming air as NW winds come down the mountains toward us. So I'd guess the rain and melted snow/ice left over will do a lot of evaporating before temps fall back below freezing on Wednesday night. Hope so anyways.
Member Since: September 4, 2007 Posts: 0 Comments: 1386
573. bwi
Current Hourly Weather Observations:

Washington National Cloudy 36 31 82 S3 30.15F Haze
Dulles Intl. Cloudy 33 30 88 SW3 30.13F Fog
BWI Airport Cloudy 33 31 92 CALM 30.13F Fog
Member Since: September 4, 2007 Posts: 0 Comments: 1386
572. zotty
Good Afternoon- 24 degrees in White Plains, NY (20-30mi N of NYC), down from 27 a few hours ago.  I just scraped off a half an inch of ice off of my car.  After clearing the windows and driving around for a bit, I determined I had to clean the ENTIRE car off.  The ice weighed a ton (literally)!  The car handled poorly and had trouble stopping with all the added weight.  i'd recommend people take the time to clear the whole car, or leave a LOT of room for breaking.
Roads are in reasonably good shape.  A lot of sand has offered traction.  
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BWI, what do you suppose they think that water sitting around on the ground is going to do as the storm passes to the east and the cold air comes in behind it?
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Blizz I know you wanted to sit back and watch this one. I hope you're enjoying it
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569. bwi
NOAA sites much improved.

LWX sounds like they don't believe temps will fall below freezing down below the PA border.

NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1258 PM EST TUE FEB 1 2011


-- Changed Discussion --SPL 18Z BALLOON IS CURRENTLY IN THE AIR.

* JUST A QUICK THOT UPDATE - MDLS CONT TO TREND WARMER FOR TEH
OVRNGT HRS...EVEN UP TO THE MASON DIXON LN. THE AREA OF THE 2
SEGMENT FZRA ADVSRY WL RMN UNCHGD...BUT WL LKLY BE TRIMMING A
FEW HRS OFF THE END TIMES OF BOTH W/ THE MID AFTN FCST PCKG.

ENTIRE MRNG HAS BEEN SPENT ON DECIDING WHAT TO DO REGARDING TNGT`S
WX. EVERYTHING KEEPS TRENDING WARMER. AM NOT SEEING TEMPS WL BE
COLD ENOUGH TO PRODUCE THE AMT OF ACCRETION NEEDED TO JUSTIFY A
WRNG. IF THAT TREND CHGS THE AREA WHERE AN UPGRADE WOULD BE MOST
LKLY WOULD BE IMMEDIATELY ALONG THE MD BORDER.

PLAN IS GOING TO BE TO GO W/ A TWO PART ADVSRY - ONE THAT WL GO FM
MINERAL TO CLARKE TO MONTGOMERY TO BALT CITY FM LATE THIS EVE TO
MID MRNG WED. THE 2ND WL BE A "LESSER" ADVSRY FM GRANT TO WARREN
TO DC AND ANNE ARUNDEL AND END BY SUNRISE. IN THE "GRTR" ADVSRY AMTS
ALONG THE BRDR COULD SEE ARND .15" OF ICE. THERE SUB FRZG AIR WL
BE THE LAST TO SCOUR. IT`S PSBL THAT IN PLACES LK LOUDOUN AND
MONTGOMERY THERE COULD BE A BIG DIFFERENCE BTWN THE NRN AND SRN
PARTS OF THE COUNTIES. IN THE "LESSER" COUNTIES ACCRETIONS WL BE
UNDER 1/10".

ANOTHER FACTOR TO CONSIDER IS THAT TEMPS LOOK TO BE RISING
OVRNGT...AND BY THE TIME THE HEAVIEST PCPN OCCURS...ARND
SUNRISE...THE MAJORITY OF THE AREA WL BE ABV FRZG. REGARDLESS -
STUDIES HV SHOWN THAT HVY RAFL RATES DOES NOT EQUATE TO HIGH
ACCRETION RATES - IDEALLY YOU WANT A PERSISTENT LGT RA IN TEMPS WELL
BLO FRZG. MUCH OF THE LIQUID FALLING LATE TNGT...EVEN IF TEMPS ARE JUST BLO
FRZG...WL RMN IN LIQUID FORM AFTR IT REACHES THE GRND.

Member Since: September 4, 2007 Posts: 0 Comments: 1386
double post.....
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Blizz, what would you recommend as the best way to monitor the development of the coastal low?

I've been checking pressure readings from weather stations on long island down to VA trying to get an idea of where it might form, but I feel like a blind squirrel. any maps, like water vapor, that there might be some clues on?

seems the lowest pressures on the coast are in the VA beach / Delaware area as of this post.
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About Blizzard92

Cornell University- Atmospheric Sciences Undergrad; Research Assist.- Onset of Spring Indices Toolbox; Interests- Small spatial scale climatolology

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Updated: 10:37 AM EST on January 18, 2014

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