Deep South Winterwx Discussion 2015-2016

[Brent]

*moves to the beach*

Snow there and not here, LOL

[Ivanhater]

12z GFS still on bored with a cold and snowy Christmas

[hurley311]

Ok....I am new so....What does all that mean?

[wxgirl69]

Does it show snow for Houston?

[vbhoutex]

To Hurley and wxgirl the answer is that those two particular model plots show snow along the Gulf Coast from TX to NW FL on Christmas day.

[hurley311]

WOW!! I sure hope so...would love to see it!! Would make a lovely Christmas.

[attallaman]

:uarrow: To Hurley and wxgirl the answer is that those two particular model plots show snow along the Gulf Coast from TX to NW FL on Christmas day.

What's the formula for a lot of snow to develop? Very cold air must move in first followed by lots of rain or is it the rain must move in first followed by lots of cold air? Does the dewpoint level determine if you will get lots of snow or not? When Houston was getting snowed on a week or so ago I had very cold air here, lots of rain but very little snow but communities about 100 miles to my north saw lots of snow, several inches of snow.

So the L that caused Houston to get the snow recently, if that L had been located further to the S, if that L had been located to my S would my area had received more snow like the areas well to my N or not? I'd like to see some snow too rather than very cold temps with lots of rain. Temperatures aren't that cold here today but I am getting lots of rain. This is a good day to just stay inside and have a pot of homemade soup cooking slowly on the stove while you're sitting by the fire sippin' on some Winn Dixie egg nog.

[Brent]

36 and raining. Someone PLEASE put me out of my misery.

[Ivanhater]

[vbhoutex]

:uarrow: To Hurley and wxgirl the answer is that those two particular model plots show snow along the Gulf Coast from TX to NW FL on Christmas day.

What's the formula for a lot of snow to develop? Very cold air must move in first followed by lots of rain or is it the rain must move in first followed by lots of cold air? Does the dewpoint level determine if you will get lots of snow or not? When Houston was getting snowed on a week or so ago I had very cold air here, lots of rain but very little snow but communities about 100 miles to my north saw lots of snow, several inches of snow.

So the L that caused Houston to get the snow recently, if that L had been located further to the S, if that L had been located to my S would my area had received more snow like the areas well to my N or not? I'd like to see some snow too rather than very cold temps with lots of rain. Temperatures aren't that cold here today but I am getting lots of rain. This is a good day to just stay inside and have a pot of homemade soup cooking slowly on the stove while you're sitting by the fire sippin' on some Winn Dixie egg nog.

Usually, the formula for snow in the deep South is pretty much as you stated it, but the biggest kicker is usually are all the layers of the atmosphere at or below freezing all the way to the surface? Since the cold air is usually very shallow by the time it gets to our areas, it is often difficult to accomplish this, so it is somewhat difficult to get snow here in the deep south. What the models are currently showing is cold/below freezing air all the way to the surface with overrunning precipitation which will usually result in snow if this air is at all levels. Ther is more to it than this, but I am not totally sure how to state it and don't want to bore everyone. A pro met or someone more versed in weather than me may be able to add to or deduct from what I stated if I am incorrect.

[JonathanBelles]

Very correct vbhoutex! Quite hard to explain without a bunch of soundings, but the more freezing air a moisture particle has to go through, the more it will be like snow. It also depends on where the freezing air is in relation to the ground and how warm the bottom of the atmosphere is.

This lesson from JetStream gives a slightly more lengthy explanation with pictures (towards the bottom)

http://www.srh.noaa.gov/srh/jetstream/s ... precip.htm

[vbhoutex]

Very correct vbhoutex! Quite hard to explain without a bunch of soundings, but the more freezing air a moisture particle has to go through, the more it will be like snow. It also depends on where the freezing air is in relation to the ground and how warm the bottom of the atmosphere is.

This lesson from JetStream gives a slightly more lengthy explanation with pictures (towards the bottom)

http://www.srh.noaa.gov/srh/jetstream/s ... precip.htm

Thanks for the assist Fact!! the graphics help a lot,

[attallaman]

These are model runs, correct? I finally was told how to read the dates on each one at the bottom of the graphics, I see where L pressure will be forming and coming over my area, now do these model images also show what the temperatures will be in any given area? What does the blue line in one that had a -10 represent? Will it be -10 degrees F or C at the surface on the date in question on the map that indicated that or is that -10 degrees F or C a temperature in the upper atmosphere, not at the surface?

[severe]

Yes, they are temperatures aloft, believe those show 850 MB......because if I saw -10 at ground level in the Houston area the end of time would soon follow.
I'm not too sure on the policies of posting links here so I'll post a quote and post the link to the article.

In the cool season, an important 850 temperature is the zero degree isotherm. If the temperature at 850 is above freezing (especially if more than 2 C above freezing), precipitation is likely to NOT fall as snow according to that forecast model. Freezing temperatures at 850 mb can support snow or some other form of frozen precipitation. Sleet or freezing rain at the surface can occur when the 850 mb temperature is above freezing. Check the surface and 1000 mb temperatures (among other parameters) for this potential.
Rest of the article HERE.
http://www.theweatherprediction.com/habyhints/103/

These models are nice to a degree for showing possible trends in the days ahead, but I wouldn't put much stock in future models 10 days out.

[attallaman]

Yes, they are temperatures aloft, believe those show 850 MB......because if I saw -10 at ground level in the Houston area the end of time would soon follow.
I'm not too sure on the policies of posting links here so I'll post a quote and post the link to the article.

In the cool season, an important 850 temperature is the zero degree isotherm. If the temperature at 850 is above freezing (especially if more than 2 C above freezing), precipitation is likely to NOT fall as snow according to that forecast model. Freezing temperatures at 850 mb can support snow or some other form of frozen precipitation. Sleet or freezing rain at the surface can occur when the 850 mb temperature is above freezing. Check the surface and 1000 mb temperatures (among other parameters) for this potential.
Rest of the article HERE.
http://www.theweatherprediction.com/habyhints/103/

These models are nice to a degree for showing possible trends in the days ahead, but I wouldn't put much stock in future models 10 days out.

Thanks for the info.

[timNms]

Interesting long term discussion from NWS Jackson:

THURSDAY NIGHT THROUGH SUNDAY...

THE FORECAST FOR THE LONGER RANGE PERIODS IS OF LOWER THAN AVERAGE
CONFIDENCE GIVEN INCONSISTENCIES BETWEEN THE GFS AND ECMWF MODELS.

THE OPERATIONAL GFS IS KEEPING THE THE FORECAST AREA UNDER DRY
NORTHWEST FLOW AS WE GO FROM LATE WEEK INTO THE WEEKEND...AND IT
DE-EMPHASIZES SRN STREAM SHORTWAVE ENERGY THEREBY KEEP ANY GULF LOW
DEVELOPMENT SUPPRESSED WELL TO OUR SOUTH. THE 00Z ECMWF ON THE OTHER
HAND CONTINUES TO SUGGEST THAT SRN STREAM SHORTWAVE ENERGY WILL DIG
SWD OVER NRN MEXICO AND HELP INDUCE A NW GULF LOW THAT WOULD BRING
LIGHT-MDT RAINFALL TO THE SRN HALF OF THE FORECAST AREA FROM THURS
NIGHT AND FRIDAY. THE ECMWF IS ALSO MORE AGGRESSIVE IN DIGGING NRN
STREAM SHORTWAVE ENERGY SWD THROUGH THE PLAINS THUS BRINGING COLDER
AIR AND THE POTENTIAL FOR A FEW SNOW SHOWERS AS WE GO INTO SUNDAY.

[attallaman]

Interesting long term discussion from NWS Jackson:

THURSDAY NIGHT THROUGH SUNDAY...

THE FORECAST FOR THE LONGER RANGE PERIODS IS OF LOWER THAN AVERAGE
CONFIDENCE GIVEN INCONSISTENCIES BETWEEN THE GFS AND ECMWF MODELS.

THE OPERATIONAL GFS IS KEEPING THE THE FORECAST AREA UNDER DRY
NORTHWEST FLOW AS WE GO FROM LATE WEEK INTO THE WEEKEND...AND IT
DE-EMPHASIZES SRN STREAM SHORTWAVE ENERGY THEREBY KEEP ANY GULF LOW
DEVELOPMENT SUPPRESSED WELL TO OUR SOUTH. THE 00Z ECMWF ON THE OTHER
HAND CONTINUES TO SUGGEST THAT SRN STREAM SHORTWAVE ENERGY WILL DIG
SWD OVER NRN MEXICO AND HELP INDUCE A NW GULF LOW THAT WOULD BRING
LIGHT-MDT RAINFALL TO THE SRN HALF OF THE FORECAST AREA FROM THURS
NIGHT AND FRIDAY. THE ECMWF IS ALSO MORE AGGRESSIVE IN DIGGING NRN
STREAM SHORTWAVE ENERGY SWD THROUGH THE PLAINS THUS BRINGING COLDER
AIR AND THE POTENTIAL FOR A FEW SNOW SHOWERS AS WE GO INTO SUNDAY.

Well one thing my area does not need is anymore rain but unfortunately according to my latest local weather forecast my area is forecasted to receive more rain this week. I'll just be glad to see the sun again.

[carolina_73]

Going by the GFS model run above would NC/SC be getting rain or snow from that LP?

[Ivanhater]

Top 3 rainiest cities in the U.S

1.Mobile, AL
2.Pensacola,FL
3.New Orleans, LA

Not surprising lately

[Brent]

Top 3 rainiest cities in the U.S

1.Mobile, AL
2.Pensacola,FL
3.New Orleans, LA

Not surprising lately

My yard is flooded and a muddy mess and it's raining AGAIN. Ughhhhhh.

On another note, check out the Euro for Sunday-Tuesday. Wow! Much colder than the GFS(and it's already cold, I could see 30's for highs here), I'll keep quiet on precip but it looks "interesting" to say the least.