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Southeast February Mid/Long Range Discussion II


Marion_NC_WX

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Yeah, it isn't as much cold chasing moisture as I had thought especially for Raleigh and WC NC, which get a few inches per 0Z Goofy.

Is anyone staying up for the good doctor? I'm tempted to hit the sack.

I don't see where you are getting accumulating snow from in NC. Both the surface temperatures and the air aloft are well above freezing until the moisture has left or is almost gone in all of NC, especially in the Raleigh area. This appears to me to be a classic case of the cold chasing the moisture.

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I don't see where you are getting accumulating snow from in NC. Both the surface temperatures and the air aloft are well above freezing until the moisture has left or is almost gone in all of NC, especially in the Raleigh area. This appears to me to be a classic case of the cold chasing the moisture.

It's there. No reason to talk specifics of an event 200+ hours out but I'll give it a go.

The precip for Raleigh in question is between 240-252...the 540 line is on top of I-85 at 240 and in SC to the OBX by hr 252. Not to mention 850mb temps are well ok. Surface temps are -2c by 252 as well.

Here is the critical thickness:

@240

VBYN9.gif

@252

rPu5N.gif

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It's there. No reason to talk specifics of an event 200+ hours out but I'll give it a go.

The precip for Raleigh in question is between 240-252...the 540 line is on top of I-85 at 240 and in SC to the OBX by hr 252. Not to mention 850mb temps are well ok. Surface temps are -2c by 252 as well.

Here is the critical thickness:

@240

VBYN9.gif

@252

rPu5N.gif

You are correct, there is no need to analyze the details on something this far out since it is unlikely to occur, but this model is not showing accumulating snow in NC. There are only a few hundredths of an inch of precipitation that falls during that time period. And surface temps are no where near -2 at hour 252. They are close to 0 and that's not going to lead to accumulating snow with very light precipitation rates. At best it is a few flakes at the end and event that is questionable as the air really drys out fast behind this system.

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You are correct, there is no need to analyze the details on something this far out since it is unlikely to occur, but this model is not showing accumulating snow in NC. There are only a few hundredths of an inch of precipitation that falls during that time period. And surface temps are no where near -2 at hour 252. They are close to 0 and that's not going to lead to accumulating snow with very light precipitation rates. At best it is a few flakes at the end and event that is questionable as the air really drys out fast behind this system.

30F = -1.11 so I was 0.89C off. That's closer to -2C than it is to 0C. There is accumulating snow in NC as a whole, which was your original inquiry. According to the model, there are rates of 0.5"/hr in the mountains...enough for accumulating snow in NC through hour 252 IMO...can't read into the models any more than this without loading bufkit.

57asC.gif

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30F = -1.11 so I was 0.89C off. That's closer to -2C than it is to 0C. There is accumulating snow in NC as a whole, which was your original inquiry. According to the model, there are rates of 0.5"/hr in the mountains...enough for accumulating snow in NC through hour 252 IMO...can't read into the models any more than this without loading bufkit.

57asC.gif

At hour 240 it is well above freezing at the surface and the precipitation is all but finished. I will admit that the mountains have a shot of an inch or two in the highest elevations, but anywhere outside of the mountains would not see anything outside of a flake or two in the air at best.

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Good morning. Looks like the 00z Suite started to converge on the idea that Areas in the Tennessee Valley region from Northern Arkansas, to Nrn Miss, Tennessee, Nrn Alabama and Nrn GA into the Carolinas need to monitor closely the developments around Monday night into Tuesday Early Morning. CMC/Nogaps/DGEX/ and even Euro are all on board of showing the moisture catching up to the Quickly evading cold airmass on the way out of the area next week. They show two disturbances moving through the area. The first arrives Monday night/Tuesday with some residual borderline cold air in place and the second a possible severe weather maker by Thursday. 00z Models show what coul be a possible quick Thumping of Snow for the Tennessee Valley areas Monday night into Tuesday morning moving from west to east. Now rather it sticks and accumulates would depend on temps and rates as we probably will be at or just above freezing but an interesting timeframe possible. GFS is not onboard of course last week it was the only model showing this potential but has since backed off. We will have to see if this trends better or worse todayt on the 12z Suite. Here are some images from last nights 00z Suite...

00z CMC:

f126.gif

f132.gif

f138.gif

Nogaps:

nof120.gif

nof132.gif

DGEX:

dgexf126.gif

Euro:

midnightmon.jpg

Uploaded with ImageShack.us

3amtueeuro.png

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30F = -1.11 so I was 0.89C off. That's closer to -2C than it is to 0C. There is accumulating snow in NC as a whole, which was your original inquiry. According to the model, there are rates of 0.5"/hr in the mountains...enough for accumulating snow in NC through hour 252 IMO...can't read into the models any more than this without loading bufkit.

Jon, stop trying you will never win the argument, it will continue until you finally ignore the conversation, trust me

57asC.gif

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AFD snippet from GSP:

THE LATEST 00Z GFS AND THE ECMWF SHOW BETTER

CONSISTENCY WITH THE TIMING OF A WEAK UPPER LEVEL SHORTWAVE SWINGING

ACROSS OUR CWFA BETWEEN 12Z AND 18Z TUESDAY. AS THICKNESS VALUES

DECREASE QUIT A BIT IN RESPONSE TO THE SHORTWAVE PASSAGE...OVERNIGHT

TEMPERATURES WILL BE COLD ENOUGH FOR WINTRY TYPE PCPN ACROSS MUCH OF

THE REGION. THEREFORE...I KEPT AT LEAST SLIGHT CHANCE POPS IN FOR

SNOW OVER THE MOUNTAINS/FOOTHILLS WITH RAIN SNOW MIX OVER THE LOWER

PIEDMONT AREA THROUGH TUESDAY MORNING. ANY WINTRY PCPN WILL SWITCH

TO RAIN SHOWERS AFTER SUNRISE AS TEMPERATURES RISE ABOVE FREEZING

LVL. ANOTHER SURFACE HIGH WILL BUILD INTO THE REGION FOR DRY

CONDITIONS WITH MODERATING TEMPERATURES TUESDAY AFTERNOON INTO

WEDNESDAY.

AFD snippet from ATL:

TIMING OF PRECIPITATION ON LATE MONDAY

NIGHT/EARLY TUESDAY MORNING MAY COINCIDE WITH COLD AIR...LEADING TO

SNOW IN THE NORTH GEORGIA MOUNTAINS AND COLD RAIN WELL INTO METRO

ATLANTA. WHILE CONFIDENCE FOR THIS EVENT IS LOW...IT BEARS WATCHING

FOR TRENDS.

AFD snippet from MEG:

MONDAY THROUGH THURSDAY...THE LONG RANGE SOLUTIONS ARE STILL ON

TRACK WITH A PROGRESSIVE UPPER SPLIT FLOW AND A SERIES OF

TROUGH/RIDGE COUPLETS PASSING THROUGH OUR AREA. THE FIRST TROUGH

WILL MOVE IN MONDAY MID MORNING THROUGH EVENING WITH WHAT APPEARS

TO BE AN ALL LIQUID PRECIPITATION EVENT. ANY CHANGES IN EARLIER

TIMING MAY REFLECT A HINT OF AN INITIAL FROZEN PRECIP AS PARTS OF

THE MIDSOUTH REMAIN ON THE EDGE OF EXITING WEEKEND AIRMASS.

AFD snippet from Little Rock:

SURFACE HIGH PRESSURE WILL MOVE EAST SUNDAY...WITH COOLER AIR

REMAINING ACROSS THE STATE. MOISTURE WILL TAKE SOME TIME TO MOVE

NORTH FROM THE GULF...WITH PRECIPITATION HOLDING OFF UNTIL AFTER

MIDNIGHT. IN ADDITION...DUE TO THE MOISTENING OF THE COLUMN...THERE

WILL LIKELY BE SOME SLEET MIXING IN WITH THE ONSET OF PRECIPITATION.

THE MAIN QUESTION WILL THEN BE IF THERE WILL BE WARMER AIR ABOVE THE

SURFACE...WITH THE POTENTIAL FOR FREEZING RAIN. AS THE WARMER AIR

MOVES FARTHER NORTH...THERE WILL BE A SWITCHOVER TO ALL RAIN...EVEN

ACROSS THE NORTH...DURING THE AFTERNOON HOURS.

THIS WILL CONTINUE TO BE MONITORED...AS THE MORNING COMMUTE MONDAY

MAY BE AFFECTED...AND ANY MINOR CHANGE IN TEMPERATURE...SPEED...OR

MOISTURE COULD DRAMATICALLY AFFECT THE FORECAST.

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FFC thinks snow...

ATURDAY...CONTINUED AGREEMENT FROM 00Z GFS AND 00Z ECMWF...EVEN THE

00Z NAM HAS JOINED THE FRAY...WITH TROUGH PASSAGE EXPECTED BETWEEN

06Z AND 12Z. THIS TIMING OPENS THE WINDOW FOR THE POSSIBILITY OF A

WINTRY WAKE-UP IN THE NORTH GEORGIA MOUNTAINS ON SATURDAY MORNING.

00Z SATURDAY MODEL SOUNDINGS SHOW DRY AIR NEAR THE SURFACE UP IN

NORTH GEORGIA THAT WOULD BE RIPE FOR EVAPORATIONAL COOLING. BY

06Z...MODEL SOUNDINGS CLEARLY DEMONSTRATE EVAPORATIONAL COOLING

CLOSE TO THE SURFACE THAT HELPS CREATE A BELOW-FREEZING COLUMN WHICH

IS NECESSARY FOR SNOW. MODEL SOUNDINGS PERSIST WITH THE MOIST BELOW

FREEZING COLUMN THROUGH 12Z. WITH SURFACE TEMPERATURES HOVERING

AROUND FREEZING...SNOW MAY STICK LIGHTLY TO GRASSY SURFACES IN THE

MOUNTAINS. THE MODEL SOUNDINGS FOR METRO ATLANTA AND POINTS SOUTH

SHOW A WARMER COLUMN WHICH WOULD KEEP ANY PRECIPITATION LIQUID.

SUNDAY/MONDAY...DRIER AIR FILTERS IN BEHIND THE SYSTEM BRINGING

LOWER RELATIVE HUMIDITIES TO NORTH AND CENTRAL GEORGIA. LARGE

PORTIONS OF THE CWA COULD FALL BELOW THE 25 PERCENT RELATIVE

HUMIDITY THRESHOLD CRITICAL FOR FIRE WEATHER CONCERNS ON SUNDAY AND

MONDAY AFTERNOONS. TIMING OF PRECIPITATION ON LATE MONDAY

NIGHT/EARLY TUESDAY MORNING MAY COINCIDE WITH COLD AIR...LEADING TO

SNOW IN THE NORTH GEORGIA MOUNTAINS AND COLD RAIN WELL INTO METRO

ATLANTA. WHILE CONFIDENCE FOR THIS EVENT IS LOW...IT BEARS WATCHING

FOR TRENDS.

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Things will get interesting for the end of the week into Saturday. I think this low may be deeper and stronger than what the current models are forecasting. The next 48 hours will be fun to watch. I am excited about this weekend here in the mountains. Might get some pretty good snow but cold wil be nice to have around. Alos next week has my interest peeked. It is a few days out but the models have been having an event happen at the onset of precip for a couple of runs.

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Possible late phase on the NAM on EC coming?

No, only thing I see that is different from yesterday is the southern vort being stronger and not dampening out as quickly as it moves east along the gulf coast. Frontal passage is well after this disturbance and associated moisture move through, implying no phase, and too warm for everyone. Mountains and maybe the foothills have a shot a -SN with the northern stream and flow behind it. I think some are forgetting, or do not know what a phase means and looks like.

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Things will get interesting for the end of the week into Saturday. I think this low may be deeper and stronger than what the current models are forecasting. The next 48 hours will be fun to watch. I am excited about this weekend here in the mountains. Might get some pretty good snow but cold wil be nice to have around. Alos next week has my interest peeked. It is a few days out but the models have been having an event happen at the onset of precip for a couple of runs.

Any reason to that line of thinking? I want to believe but just curious to why you think so.

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The 12Z NAM is VERY close to being a wintry threat for some parts of the southeast/Carolinas this weekend (especially VA).

Looks like va north to me, DC area may pick up an advisory level event. Note how it has trended warmer for NC, taking the 850 line from I95 on the 0z run @ 57 compared to almost I77 @ 45hrs this run. Coastal low is a little stronger and just off HAT, throwing more warm air inland. The cold front is just coming over the mtns at this time so there is really mechanism to prevent this "warm up.". I think we may even see it trend warmer, with a stronger moisture influx, taking SE VA out of the game, but DC is looking better than 24hrs ago that's for sure.

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