Mountain City Weather Center Weblog

I was blessed with the chance to live in Colorado for about 6 months last year- Breckenridge to be exact. During my time out there, it sure was interesting getting an opportunity to study the weather across such a rugged area. While weather forecasting in any location is certainly a challenge, trying to forecast the weather in the Rockies (directly along the continental divide) was particularly rough.

When you consider the fact that the eastern part of the state (roughly from Denver east to the KS border) is flat as a pancake, though high in elevation (around 5k feet on average) and the western half of the state features some of the most rugged mountains in the country (with elevations soaring close to 15k feet in some places), you have the makings for some “fun” forecasting and weather events.

I spoke with several friends from CO yesterday. At the same time tornadoes were dropping on the eastern half of CO, snow was flying in Breckenridge (the town sits at an elevation of 9600 feet), and accumulating! At the same time, of course, damaging tornadoes were wrecking havoc on the eastern communities, along with extremely large hail storms (baseball sized hail was reported). All in all, however, this was just another day in Colorado, and really not that out of the ordinary!

Below I’ve posted a few links to the rough weather that plagued “my second home” yesterday. If you get some time, read over these stories…some of the weather reports are quite impressive.

http://www.cnn.com/2008/US/05/22/colorado.tornado.video/index.html
http://www.9news.com/news/top-article.aspx?
http://www.crh.noaa.gov/bou/?n=severe_reports_052208

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 136
NWS STORM PREDICTION CENTER NORMAN OK
545 PM EDT WED MAR 19 2008

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

EXTREME WESTERN NORTH CAROLINA
EASTERN TENNESSEE
WESTERN VIRGINIA
SOUTHERN WEST VIRGINIA

EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 545 PM UNTIL
1000 PM EDT.

HAIL TO 0.5 INCH IN DIAMETER…THUNDERSTORM WIND GUSTS TO 70
MPH…AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 50
STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES NORTH
NORTHEAST OF BECKLEY WEST VIRGINIA TO 55 MILES SOUTH OF KNOXVILLE
TENNESSEE. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).

REMEMBER…A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION…CONTINUE…WW 135…

DISCUSSION…A FORCED CONVECTIVE LINE ALONG COLD FRONT WILL CONTINUE
TO SPREAD QUICKLY EWD AS A STRONG MID LEVEL WAVE EJECTS NEWD TOWARD
WV/PA. A NARROW CORRIDOR OF DESTABILIZATION IN ADVANCE OF THE LINE
SHOULD HELP MAINTAIN SUFFICIENT INSTABILITY FOR THUNDERSTORMS AND AN
ATTENDANT THREAT FOR DAMAGING WINDS AT THE SURFACE…IN AN
ENVIRONMENT OF VERY STRONG LOW-MID LEVEL FLOW.

AVIATION…A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 350. MEAN STORM
MOTION VECTOR 24050.

A nasty squall line is developing over central east TN this afternoon. This line has already spawned four severe thunderstorm warnings and two tornado warnings over eastern middle TN this afternoon.

A Tornado Watch is up for central east TN until 9PM, and this could be extended into our region, providing the line of storms holds together. Again, isolated damaging wind gusts and large hail is the primary concern with this line of storms, although an isolated tornado is certainly possible.

We’ll keep an eye on this line as it progresses east.

MESOSCALE DISCUSSION 0474
NWS STORM PREDICTION CENTER NORMAN OK
0132 PM CDT WED MAR 19 2008

AREAS AFFECTED…MIDDLE/ERN TN…SERN KY

CONCERNING…SEVERE POTENTIAL…WATCH POSSIBLE

VALID 191832Z - 191930Z

BROKEN CONVECTIVE LINE ACROSS MIDDLE TN MAY INTENSIFY AS IT LIKELY
PROGRESSES E/NEWD INTO ERN TN/SERN KY THROUGH MID-AFTERNOON. AMIDST
A VERY FAVORABLE LOW/DEEP-LAYER SHEAR PROFILE…A BREAK IN CLOUD
COVERAGE OUT AHEAD OF THE LINE MAY PROVE ADEQUATE FOR SUFFICIENT
HEATING WITH ORGANIZED LOW-TOPPED SUPERCELL DEVELOPMENT POSSIBLE.
AREA WILL BE MONITORED FOR SIGNS OF FURTHER INTENSIFICATION AND A
POSSIBLE WW.

AS OF 1830Z…RADAR/VIS SATELLITE IMAGERY DEPICTS A BROKEN LINE OF
SHOWERS ROUGHLY FROM JACKSON TO GILES COUNTY IN MIDDLE TN…WITH A
60 MILE WIDE CORRIDOR AHEAD OF THE LINE WITH SCATTERED CLOUD
COVERAGE. THIS HAS RESULTED IN SURFACE TEMPERATURES WARMING INTO THE
LOWER TO MIDDLE 70S WITHIN THIS NARROW CORRIDOR OF GREATER
INSOLATION /PER LATEST MESONET OBSERVATIONS/. MODIFIED RUC SOUNDINGS
SUGGEST MLCAPE VALUES SHOULD BE APPROACHING 500 J/KG IN THIS
AXIS…GIVEN SURFACE DEW POINTS HOLDING IN THE UPPER 50S TO LOWER
60S. WITH AN INTENSE MID-LEVEL JET OVERHEAD /AROUND 100 KT AT 500
MB/ AND STRONG DIFFERENTIAL CYCLONIC VORTICITY ADVECTION…THE
DEGREE OF FORCING/SHEAR COULD BE SUFFICIENT FOR LOW-TOPPED
SUPERCELLS/SQUALL LINE…EVEN WITH WEAK INSTABILITY. GIVEN 0-1 KM
SRH WELL IN EXCESS OF 300 M2/S2…DAMAGING WINDS AND ISOLATED
TORNADOES WOULD BE THE PRIMARY THREATS.

..GRAMS.. 03/19/2008

ATTN…WFO…RLX…MRX…JKL…FFC…LMK…OHX…HUN…

38158267 38038206 37638184 36928266 35608408 34808520
34518574 34688632 35108638 36168562 37198456 38058319

Individual cells are starting to “pop” behind the big mass of rain currently in place across our region, and these are already borderline severe. As breaks in the cloudiness develops this afternoon behind the big mass of moisture, additional strong to severe storms will pop directly along the boundary. Big threats will be isolated reports of damaging winds and hail. The SPC could hoist a severe weather watch at anytime out ahead of this activity.

ALSO…guess what, our old pal, the GFS is now starting to see the “mischief” (per the midday model run) for Easter and Monday…

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MORRISTOWN TN
359 PM EDT TUE MAR 18 2008

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-
005-006-008-190800-
CHEROKEE-CLAY-SCOTT TN-CAMPBELL-CLAIBORNE-HANCOCK-HAWKINS-
SULLIVAN-JOHNSON-MORGAN-ANDERSON-UNION-GRAINGER-HAMBLEN-
NORTHWEST COCKE-COCKE SMOKY MOUNTAINS-NORTHWEST GREENE-
SOUTHEAST GREENE-WASHINGTON TN-UNICOI-NORTHWEST CARTER-
SOUTHEAST CARTER-ROANE-LOUDON-KNOX-JEFFERSON-NW BLOUNT-
BLOUNT SMOKY MOUNTAINS-NORTH SEVIER-SEVIER SMOKY MOUNTAINS-
SEQUATCHIE-BLEDSOE-RHEA-MEIGS-MCMINN-NORTHWEST MONROE-
SOUTHEAST MONROE-MARION-HAMILTON-BRADLEY-WEST POLK-EAST POLK-LEE-
WISE-SCOTT-RUSSELL-WASHINGTON-
INCLUDING THE CITIES OF…MURPHY…HAYESVILLE…ONEIDA…
LA FOLLETTE…TAZEWELL…SNEEDVILLE…ROGERSVILLE…KINGSPORT…
BRISTOL…MOUNTAIN CITY…WARTBURG…CLINTON…OAK RIDGE…
MAYNARDVILLE…RUTLEDGE…MORRISTOWN…NEWPORT…COSBY…
GREENEVILLE…CEDAR CREEK…JOHNSON CITY…ERWIN…ELIZABETHTON…
ROAN MOUNTAIN…KINGSTON…LENOIR CITY…KNOXVILLE…DANDRIDGE…
MARYVILLE…CADES COVE…SEVIERVILLE…GATLINBURG…DUNLAP…
PIKEVILLE…DAYTON…DECATUR…ATHENS…MADISONVILLE…
COKER CREEK…JASPER…CHATTANOOGA…CLEVELAND…BENTON…
DUCKTOWN…JONESVILLE…WISE…GATE CITY…LEBANON…ABINGDON
359 PM EDT TUE MAR 18 2008 /259 PM CDT TUE MAR 18 2008/

…STORMS WITH DAMAGING WINDS POSSIBLE WEDNESDAY…

A STRONG UPPER LEVEL SYSTEM AND AN ASSOCIATED COLD FRONT…WILL BE
APPROACHING THE TENNESSEE VALLEY AND APPALACHIANS TONIGHT…AND
WILL PUSH THROUGH THE AREA ON WEDNESDAY WITH SHOWERS AND A FEW
THUNDERSTORMS. THE THUNDERSTORMS MAY NOT HAVE MUCH LIGHTNING AND
THUNDER…BUT MOST SHOWERS AND THUNDERSTORMS WILL BE ACCOMPANIED
WITH STRONG WINDS. ALTHOUGH GUSTY WINDS CAN BE EXPECTED WITH ANY OF
THE SHOWERS OR STORMS…LOCATIONS IN HIGHER ELEVATIONS WILL BE MORE
EXPOSED TO THE HIGHEST WINDS. THE SHOWERS…STORMS…AND WINDS WILL
MOVE QUICKLY AWAY FROM THE AREA LATE WEDNESDAY AFTERNOON AND
EVENING AS HIGH PRESSURE FILLS INTO THE AREA.

STAY TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA FOR FURTHER
DETAILS OR UPDATES.

$$

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MORRISTOWN TN
322 PM EDT MON MAR 17 2008

NCZ060-061-TNZ012>018-035>047-067>074-081>087-098>102-VAZ001-002-
005-006-008-180330-
CHEROKEE-CLAY-SCOTT TN-CAMPBELL-CLAIBORNE-HANCOCK-HAWKINS-
SULLIVAN-JOHNSON-MORGAN-ANDERSON-UNION-GRAINGER-HAMBLEN-
NORTHWEST COCKE-COCKE SMOKY MOUNTAINS-NORTHWEST GREENE-
SOUTHEAST GREENE-WASHINGTON TN-UNICOI-NORTHWEST CARTER-
SOUTHEAST CARTER-ROANE-LOUDON-KNOX-JEFFERSON-NW BLOUNT-
BLOUNT SMOKY MOUNTAINS-NORTH SEVIER-SEVIER SMOKY MOUNTAINS-
SEQUATCHIE-BLEDSOE-RHEA-MEIGS-MCMINN-NORTHWEST MONROE-
SOUTHEAST MONROE-MARION-HAMILTON-BRADLEY-WEST POLK-EAST POLK-LEE-
WISE-SCOTT-RUSSELL-WASHINGTON-
INCLUDING THE CITIES OF…MURPHY…HAYESVILLE…ONEIDA…
LA FOLLETTE…TAZEWELL…SNEEDVILLE…ROGERSVILLE…KINGSPORT…
BRISTOL…MOUNTAIN CITY…WARTBURG…CLINTON…OAK RIDGE…
MAYNARDVILLE…RUTLEDGE…MORRISTOWN…NEWPORT…COSBY…
GREENEVILLE…CEDAR CREEK…JOHNSON CITY…ERWIN…ELIZABETHTON…
ROAN MOUNTAIN…KINGSTON…LENOIR CITY…KNOXVILLE…DANDRIDGE…
MARYVILLE…CADES COVE…SEVIERVILLE…GATLINBURG…DUNLAP…
PIKEVILLE…DAYTON…DECATUR…ATHENS…MADISONVILLE…
COKER CREEK…JASPER…CHATTANOOGA…CLEVELAND…BENTON…
DUCKTOWN…JONESVILLE…WISE…GATE CITY…LEBANON…ABINGDON
322 PM EDT MON MAR 17 2008 /222 PM CDT MON MAR 17 2008/

…HIGH WINDS AND SEVERE THUNDERSTORMS POSSIBLE TUESDAY NIGHT INTO
WEDNESDAY…

A STRONG UPPER LEVEL SYSTEM AND ASSOCIATED COLD FRONT WILL MOVE
INTO THE TENNESSEE VALLEY TUESDAY NIGHT AND CROSS THE EASTERN
TENNESSEE VALLEY AND SOUTHERN APPALACHIANS WEDNESDAY. THIS SYSTEM WILL
INCREASE WINDS FROM THE SOUTH TO SOUTHWEST ACROSS THE REGION
TUESDAY NIGHT AND AS IT PASSES OVER THE REGION WEDNESDAY THE
STRONG WINDS WILL CONTINUE. ALSO SHOWERS AND THUNDERSTORMS WILL
DEVELOP LATE TUESDAY NIGHT AND WEDNESDAY. SOME OF THESE THUNDERSTORMS
MAY BECOME SEVERE ESPECIALLY OVER THE SOUTHERN CUMBERLAND PLATEAU
AND SOUTHERN TENNESSEE VALLEY COUNTIES EARLY WEDNESDAY…WITH DAMAGING
WINDS THE PRIMARY THREAT. THE TIGHTENING PRESSURE GRADIENT WILL
BRING THE POSSIBILITY OF STRONG AND GUSTY WINDS…ESPECIALLY IN THE
HIGHER TERRAIN AREAS OF THE CUMBERLAND PLATEAU…AND THE SOUTHERN
APPALACHIAN MOUNTAINS OF EAST TENNESSEE…SOUTHWEST NORTH CAROLINA
AND SOUTHWEST VIRGINIA TUESDAY NIGHT AND WEDNESDAY. IF THE SYSTEM SLOWS
DOWN THE THREAT FOR SEVERE THUNDERSTORMS MAY CONTINUE THROUGH
WEDNESDAY WITH DAMAGING WINDS BEING THE MAIN THREAT.

STAY TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA FOR FURTHER
DETAILS OR UPDATES.

$$

HW

I’ve heard the NWS and Storm Prediction Center taking some “heat” from the media concerning the tornado that tracked through downtown Atlanta on Friday.  This is absurd, as the Storm Prediction Center had a Slight Risk of severe thunderstorms up for the greater ATL area and surrounding communities two days in advance.  So, I thought I’d post what the NWS defines as a slight, moderate, and high risk of severe weather…

SLIGHT RISK (SLGT RISK): At least one severe thunderstorm is expected to occur in or close to the area, which means that tornadoes, large hail, severe straight-line winds and very intense rain may occur, but rather isolated and probably with marginally severe intensity. Additionally, widespread non-severe thunderstorms are possible.

MODERATE RISK (MDT RISK): The chances of very large hail (something like baseball size) and intense downbursts are quite high, as well as for tornadoes - which are generally possible with any thunderstorm, however, a tornado is more likely with organized long-lived severe convective systems (supercells, bow echoes, LEWPs) than with short-lived non-severe thunderstorms - accordingly the probability of a tornado occurrence at a given location increases with storm intensity and storm coverage.

HIGH RISK: Widespread “extreme” severe thunderstorms, very large hail, downbursts, tornadoes. This mode represents the “perfect setup” (yes, something like this does exist in Germany), which occurs maybe once or twice a year (if at all). The high risk stands for a severe-thunderstorm outbreak, quite likely with numerous tornadoes.

The SPC has gone ahead and expanded the Moderate risk area north to the TN border and east into AL for today.  I’m very concerned about the possibility of damaging tornadoes across the MDT risk area, as well as on up into western TN.  If your travels take you in west or south west of here tonight, PLEASE keep abreast of the weather situation via local media.  Severe weather outbreaks are especially dangerous after dark.

Below, I’ve posted the Day 2 Severe Weather Outlook from the SPC.  It includes our region in a slight risk of severe weather Tuesday.  Primary concern here will  be damaging straight line winds in excess of 60 MPH.  All in all, however, widespread severe weather doesn’t look to be an issue here in the mountains.

As always, keep tuned here to the BLOG and over on www.mountaincityweathercenter.com.

Below is from the NWS out of Memphis, TN.

______________________________________________________________________________________

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MEMPHIS TN
330 PM CST SUN MAR 2 2008

ARZ008-009-017-018-026>028-035-036-048-049-058-MOZ113-115-MSZ001>017-
020>024-TNZ001>004-019>021-048>055-088>092-031100-
ALCORN-BENTON-CALHOUN-CARROLL-CHESTER-CHICKASAW-CLAY-COAHOMA-
CRAIGHEAD-CRITTENDEN-CROCKETT-CROSS-DECATUR-DESOTO-DUNKLIN-DYER-
FAYETTE-GIBSON-GREENE-HARDEMAN-HARDIN-HAYWOOD-HENDERSON-HENRY-
ITAWAMBA-LAFAYETTE-LAKE-LAUDERDALE-LAWRENCE-LEE(AR)-LEE(MS)-MADISON-
MARSHALL-MCNAIRY-MISSISSIPPI-MONROE-OBION-PANOLA-PEMISCOT-PHILLIPS-
POINSETT-PONTOTOC-PRENTISS-QUITMAN-RANDOLPH-SHELBY-ST. FRANCIS-
TALLAHATCHIE-TATE-TIPPAH-TIPTON-TISHOMINGO-TUNICA-UNION-WEAKLEY-
YALOBUSHA-
330 PM CST SUN MAR 2 2008

…SEVERE THUNDERSTORMS…HEAVY RAINFALL…STRONG WIND…AND
LIGHT SNOW ACCUMULATIONS ARE POSSIBLE ACROSS THE MIDSOUTH MONDAY AND
TUESDAY AS A POWERFUL LOW PRESSURE SYSTEM MOVES THROUGH THE AREA…

THERE IS MODERATE RISK FOR SEVERE THUNDERSTORMS ACROSS NORTH
MISSISSIPPI WHILE MUCH OF THE REST OF THE MIDSOUTH IS UNDER A
SLIGHT RISK FOR SEVERE THUNDERSTORMS MONDAY INTO MONDAY NIGHT.
DAMAGING WIND OF 60 MPH OR GREATER IS THE MAIN HAZARD…BUT SMALL
HAIL AND A FEW TORNADOES MAY BE POSSIBLE AS WELL…PARTICULARLY
ACROSS NORTH MISSISSIPPI WHERE INSTABILITY WILL BE GREATEST.
THE BEST TIME FRAME FOR SEVERE STORMS WILL BE BETWEEN 2 PM AND
8 PM CST WEST OF THE MISSISSIPPI RIVER…AND BETWEEN 4 PM AND
2 AM CST EAST OF THE MISSISSIPPI RIVER…ALONG AND JUST AHEAD
OF A STRONG COLD FRONT.

WIDESPREAD HEAVY RAINFALL OF 1 TO 2 INCHES CAN BE EXPECTED ACROSS
THE MIDSOUTH MONDAY AND MONDAY NIGHT.  THIS MAY RESULT IN MINOR
LOCALIZED FLOODING.

STRONG WINDS AROUND 25 MPH WITH GUSTS NEAR OR ABOVE 40 MPH…EVEN
AWAY FROM THUNDERSTORMS…CAN BE EXPECTED MONDAY AND MONDAY NIGHT.
ADDITIONAL WIND ADVISORIES WILL LIKELY BE NEEDED.

SNOW ACCUMULATIONS OF 1 TO 2 INCHES MAY OCCUR NORTH OF A JONESBORO
ARKANSAS TO HUNTINGDON TENNESSEE LINE BETWEEN 3 AM AND NOON CST
TUESDAY AS THE UPPER LEVEL TROUGH MOVES THROUGH.  THIS MAY RESULT IN
MINOR TRAVEL INCONVENIENCES.

ALL INTERESTS ACROSS THE MIDSOUTH ARE ENCOURAGED TO PAY CLOSE
ATTENTION TO THE LATEST STATEMENTS FROM THE NATIONAL WEATHER
SERVICE REGARDING THIS HIGH IMPACT WEATHER SYSTEM.

$$

MBS/CJC