SW LA/SE TX Winter 2013-2014

[ravyrn]

[BigB0882]

I finally got meteostar to refresh for the 00z GFS and I have never seen this before but it is EXACTLY the same as the 18z. Same everything during the event, precip amounts, temps, etc. I have never seen that. That is the ultimate consistency. I know we are close to the event but still far enough out for some changes. I almost wonder if they haven't completely updated it all. Going to keep refreshing it in a bit to see.

[BigB0882]

Nevermind, it was updated and reflects higher QPF. .7 for BTR. Of that, it looks like .30 would be all snow. That would be 1.5 to 3 inches. if you go with 5:1 or 10:1 ratios. What mainly determines those ratios? Temps? Anyone know anything about that.

[ravyrn]

BigB, here's a meteogram per the 0Z GFS for BR. The coordinates are the intersection of Florida/190 and S. Foster



This looks very good for you.

[BigB0882]

Thanks. That does look nice. I am going to be no good at work tomorrow trying to check the models runs.

[Ntxw]

Thanks. That does look nice. I am going to be no good at work tomorrow trying to check the models runs.

Snow is an addiction, once you get hooked it ruins you! . Never going back

[BigB0882]

I am a teacher, though! My poor students aren't going to learn a darn thing tomorrow. haha

[CajunMama]

BigB0882, you think that's bad. I have to report for freaking US Federal District Court Jury Duty. That means NO CELL PHONES in the federal court house. How will I survive????????

Thanks ravyrn!

[windnrain]

Wow. Never thought I'd have to post in this forum. I'm usually only here for hurricane season.

So I am in BTR myself. We're just coming out of a recent winter storm. It was pretty crazy! Lots of ice all over, shut down the interstates for an entire day and a half! It was wild, some of the craziest weather I've seen here.

So here is what I am drawing, please seasoned winter vets and people used to this correct me if I am wrong:

- This event will be bigger than the one a couple of days ago. Precipitation totals were not expected to be as high as the one a couple days ago as they are for this one.

- There is something called a changeover... when 850mb temps cross into 32 degrees, freezing rain/sleet become snow.

- From what I am gathering, BTR will hit that point after about .3 inches of precipitation.

- .3-.4 inches of precip will be snow.

- .3-.4 inches of precip will be freezing rain and or sleet.

- .3-.4 inches of precip in terms of snow, from what I am reading about a 10inch conversion ratio, leaves us with an estimate of 3 inches of snow give or take.

- .3-.4 inches of precip as freezing rain and sleet could be very perilous. Sleet accumulates at, what I am reading, a 3-1 ratio and we would get freezing rain before we got sleet. Significant glazing could occur. I have not found a good conversion fro inches of precip to inches of freezing rain glazing, but I am guessing that .3-.4 inches of precip leaves us with at least half of that being glazing, correct? or is it a bigger ratio? Even if it was .25 inches of glazing, that would be bigger than the last one that hit. Just that was enough to cause some power outages and plenty of wrecks.

- Ultimately, from my research, I'm getting .25-.5 inches of ice and 3 inches of snow as the best guess. If this happens... things are going to be pretty crazy here.

Right? Or wrong?

How can I look at these charts and determine freezing rain vs sleet by the way?

[ravyrn]

Jagno, I'm not familiar with the zip codes as I've been out of LCH for a while now. I made one for LCH airport and I have one for Sulphur I had made for a friend on FB earlier. Here they are, I hope they can give you an idea of what to expect.




It's worth noting the NAM is slightly warmer and drier, but I won't make a meteogram for it as I think the GFS is more reliable.

If I were to guess, it's gonna be freezing rain > sleet > snow w/ about 2" of snow after the changeover. Good luck on receiving snow over the ice. The event will begin around noon Tuesday. I recall you said you have 38 employees, so I'd consider closing at lunch Tuesday and probably not opening Wednesday.

edit: It may start around 9am after taking a closer look. I'd maybe contact NWS LC tomorrow after the 12Z and see what they think if you're in charge of whether or not that many employees drive to work in possibly dangerous conditions.

[Jagno]

Thank you Ravyrn!

I am really trying to get a handle on this system with very little success. I can't figure out how some forecasts are calling for 5+ inches of snow east and west of me yet we are still forecasted for 1/4" sleet and a slight chance of a change over to snow. So from what I'm seeing we should be okay to keep our business open normal hours until 10pm on Monday without endangering ourselves or our staff. We will close Tuesday and Wednesday from what I'm seeing.

[windnrain]

Another question - why do most weather agencies project BTR as getting 1 inch of snowfall to 2 inches of snowfall? This seems on the low end? And most don't mention much in terms of freezing rain/sleet save for "it could happen."

Here though, and from the models, it seems like a much bigger event. There's no way that .7 inches of precip during all of this would only translate to 2 inches of snow and negligible freezing rain, right?

They really whiffed the forecast for this last storm a few days ago too. They said that the precip would be over by lunch the next day. It was still going well into the afternoon and evening. Furthermore they said the high would be 40 degrees. It didn't even break freezing!

I'm a lot more used to tropical weather reporting, tracking, etc. This is VERY new to me in Baton Rouge!

[ravyrn]

Thank you Ravyrn!

I am really trying to get a handle on this system with very little success. I can't figure out how some forecasts are calling for 5+ inches of snow east and west of me yet we are still forecasted for 1/4" sleet and a slight chance of a change over to snow. So from what I'm seeing we should be okay to keep our business open normal hours until 10pm on Monday without endangering ourselves or our staff. We will close Tuesday and Wednesday from what I'm seeing.

I'm not a professional, but I'm not seeing where the snowy forecasts are coming from in the model data GFS/NAM/EURO. I'm really concerned about the sleet potential along I-10. There does seem to be a changeover where 2" of snow could be possible per the meteogram I posted, but the sleet has me very concerned. Monday should be fine. Tues is an area for concern. I'd consult a professional if you have the means to do so.

Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

[PTrackerLA]

GFS shows about 1/3" of QPF when the temp is under 28 and 850mb temps will hit 0 for Lafayette at that time as well.

http://www.erh.noaa.gov/box/tables/snow ... water.html

Using this chart I can see that 5" is a very real possibility. The models may not be overdoing the snowfall totals by all that much. If things remain the same in the morning I'll be making a huge trip to the grocery store at noon as travel may be nearly impossible for 2 days around here.

[BigB0882]

I plan on going to the grocery store as well. I get off earlier than most so hopefully I can beat the big rush. To be honest, I don't think the stores will be too bad. Most people here don't have a clue how to plan for a major winter storm so I don't think they will even consider stocking up on stuff.

[ravyrn]

Another question - why do most weather agencies project BTR as getting 1 inch of snowfall to 2 inches of snowfall? This seems on the low end? And most don't mention much in terms of freezing rain/sleet save for "it could happen."

Here though, and from the models, it seems like a much bigger event. There's no way that .7 inches of precip during all of this would only translate to 2 inches of snow and negligible freezing rain, right?

They really whiffed the forecast for this last storm a few days ago too. They said that the precip would be over by lunch the next day. It was still going well into the afternoon and evening. Furthermore they said the high would be 40 degrees. It didn't even break freezing!

I'm a lot more used to tropical weather reporting, tracking, etc. This is VERY new to me in Baton Rouge!

000
WWUS44 KLIX 262105 CCA
WSWLIX

URGENT - WINTER WEATHER MESSAGE...CORRECTED
NATIONAL WEATHER SERVICE NEW ORLEANS LA
304 PM CST SUN JAN 26 2014

...SIGNIFICANT AMOUNTS OF WINTRY PRECIPITATION TO AFFECT SOUTHEAST
LOUISIANA AND SOUTHERN MISSISSIPPI TUESDAY AND TUESDAY NIGHT...

.A STRONG COLD FRONT WILL MOVE THROUGH SOUTHERN MISSISSIPPI AND
SOUTHEAST LOUISIANA ON MONDAY. A DISTURBANCE WILL MOVE ACROSS THE
NORTHERN GULF OF MEXICO ON TUESDAY AND SPREAD PRECIPITATION BACK
INTO THE AREA. WITH A VERY COLD AIRMASS ALREADY IN PLACE...THIS
WILL MEAN THE PRECIPITATION IS LIKELY TO FALL AS SLEET...FREEZING
RAIN...OR SNOW ACROSS MOST OR ALL OF THE AREA. THE POTENTIAL
EXISTS FOR SIGNIFICANT TRAVEL PROBLEMS FROM SNOW OR ICING DUE TO
FREEZING RAIN.

LAZ034>037-039-040-046>050-056>072-MSZ068>071-077-080>082-270530-
/O.NEW.KLIX.WS.A.0001.140128T1200Z-140129T1200Z/
POINTE COUPEE-WEST FELICIANA-EAST FELICIANA-ST. HELENA-WASHINGTON-
ST. TAMMANY-IBERVILLE-WEST BATON ROUGE-EAST BATON ROUGE-ASCENSION-
LIVINGSTON-ASSUMPTION-ST. JAMES-ST. JOHN THE BAPTIST-
UPPER LAFOURCHE-ST. CHARLES-UPPER JEFFERSON-ORLEANS-
UPPER PLAQUEMINES-UPPER ST. BERNARD-UPPER TERREBONNE-
LOWER TERREBONNE-LOWER LAFOURCHE-LOWER JEFFERSON-
LOWER PLAQUEMINES-LOWER ST. BERNARD-NORTHERN TANGIPAHOA-
SOUTHERN TANGIPAHOA-WILKINSON-AMITE-PIKE-WALTHALL-PEARL RIVER-
HANCOCK-HARRISON-JACKSON-
INCLUDING THE CITIES OF...NEW ROADS...LIVONIA...
ST. FRANCISVILLE...JACKSON...CLINTON...GREENSBURG...MONTPELIER...
BOGALUSA...FRANKLINTON...SLIDELL...MANDEVILLE...COVINGTON...
LACOMBE...PLAQUEMINE...WHITE CASTLE...PORT ALLEN...ADDIS...
BRUSLY...BATON ROUGE...GONZALES...DONALDSONVILLE...
DENHAM SPRINGS...WALKER...PIERRE PART...LABADIEVILLE...
PAINCOURTVILLE...LUTCHER...GRAMERCY...LAPLACE...RESERVE...
THIBODAUX...RACELAND...LAROSE...DESTREHAN...NORCO...METAIRIE...
KENNER...NEW ORLEANS...BELLE CHASSE...CHALMETTE...VIOLET...
HOUMA...BAYOU CANE...CHAUVIN...DULAC...MONTEGUT...GALLIANO...
CUT OFF...GOLDEN MEADOW...PORT SULPHUR...EMPIRE...YSCLOSKEY...
AMITE...KENTWOOD...HAMMOND...PONCHATOULA...CENTREVILLE...
WOODVILLE...GLOSTER...LIBERTY...CROSBY...MCCOMB...TYLERTOWN...
PICAYUNE...BAY ST. LOUIS...WAVELAND...DIAMONDHEAD...GULFPORT...
BILOXI...PASCAGOULA...OCEAN SPRINGS...MOSS POINT...GAUTIER...
ST. MARTIN
304 PM CST SUN JAN 26 2014

...WINTER STORM WATCH IN EFFECT FROM TUESDAY MORNING THROUGH LATE
TUESDAY NIGHT...

THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS ISSUED A WINTER
STORM WATCH...WHICH IS IN EFFECT FROM TUESDAY MORNING THROUGH
LATE TUESDAY NIGHT.

* TIMING...A WINTRY MIX OF PRECIPITATION COULD BEGIN AS EARLY AS
TUESDAY MORNING...WITH THE HEAVIEST PRECIPITATION EXPECTED
TUESDAY AFTERNOON AND EVENING.

* IMPACTS...SNOW AMOUNTS IN EXCESS OF TWO INCHES AND SLEET AND
FREEZING RAIN ACCUMULATIONS OF A QUARTER INCH OR MORE ARE
POSSIBLE ACROSS THE ENTIRE AREA. TRAVEL CONDITIONS ARE EXPECTED
TO BECOME DIFFICULT DUE TO ICY ROADS AND BRIDGES DURING THE DAY
ON TUESDAY. IN AREAS WHERE SIGNIFICANT FREEZING RAIN
OCCURS...SPORADIC POWER OUTAGES ARE POSSIBLE. THE HIGHEST
POTENTIAL FOR FREEZING RAIN WILL BE ACROSS SOUTHEAST LOUISIANA
SOUTH OF LAKE PONTCHARTRAIN INCLUDING THE CITY OF NEW ORLEANS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WATCH MEANS THERE IS A POTENTIAL FOR SIGNIFICANT
SNOW...SLEET...OR ICE ACCUMULATIONS THAT MAY IMPACT TRAVEL.
CONTINUE TO MONITOR THE LATEST FORECASTS.

&&

$$

[ravyrn]

This seems to say freezing rain, a lot of sleet, and then a little snow at the end to the user that requested it. 0Z GFS for Marrero, LA.

EDIT: Site is getting laggy, if you're refreshing, try to limit it to once every 15m so we don't run the site down. Also, if you want meteograms, PM me the request and I will post one for your location. I'm only doing GFS meteograms, but if you ask nicely, I may do a NAM also.

[ravyrn]

GFS shows about 1/3" of QPF when the temp is under 28 and 850mb temps will hit 0 for Lafayette at that time as well.

http://www.erh.noaa.gov/box/tables/snow ... water.html

Using this chart I can see that 5" is a very real possibility. The models may not be overdoing the snowfall totals by all that much. If things remain the same in the morning I'll be making a huge trip to the grocery store at noon as travel may be nearly impossible for 2 days around here.

I disagree. This is the 0Z GFS for the airport in Lafayette. I am not seeing 5". I certainly hope you get to see that though! According to this meteogram, temps aloft don't dip below freezing until the end. I see 2" at most.

[CajunMama]

I plan on going to the grocery store as well. I get off earlier than most so hopefully I can beat the big rush. To be honest, I don't think the stores will be too bad. Most people here don't have a clue how to plan for a major winter storm so I don't think they will even consider stocking up on stuff.

Walmart here in south Lafayette had empty shelves at 6pm Sunday evening.

[windnrain]

0z now has .41-.49 inches before 850mb drops below freezing. Not good... LOTS of freezing rain.