U.S. has a cool and very dry March; severe weather outbreak likely today

By: Dr. Jeff Masters , 1:08 PM GMT on April 17, 2013

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It was another relatively quiet month for weather extremes in the U.S. during March 2013, said NOAA's National Climatic Data Center (NCDC) in their latest State of the Climate report. The month ranked as the 43rd coolest March in the 119-year record for the contiguous U.S., and was the coolest March since 2002. This is in stark contrast to what happened in 2012, when the U.S. had its warmest March on record. Eleven states, mostly in the Southeast, experienced a top-ten coolest March on record in 2013. Remarkably, Florida, Georgia, Alabama, South Carolina, and North Carolina had March 2013 temperatures that were cooler than in January 2013. California, Nevada, and Arizona had a top-ten warmest March. The pattern of warmth in the west and cool conditions in the east was due to the fact that the jet stream was stuck in a large loop that allowed cold air to spill out of Canada into the Southeast U.S., and warm air to flow northward over the southwestern states. We can describe the jet stream behavior using the Arctic Oscillation (AO) Index, which is a measure of pressure patterns across the Arctic. During March 2013, the monthly-averaged AO index reached its most negative March value since records began in 1950.

According to NOAA's U.S. Climate Extremes Index (CEI), which tracks the percentage area of the contiguous U.S. experiencing top-10% and bottom-10% extremes in temperature, precipitation, and drought, the year 2013 has been below average for extremes. The CEI during January - March 2013 was 15%, and on average, about 20% of the contiguous U.S. experiences top-10% extreme weather as defined by the CEI.


Figure 1. Historical temperature ranking for the U.S. for March 2013. Eleven states, mostly in the Southeast, had a top-ten coldest March, and California, Nevada, and Arizona had a top-ten warmest March. Image credit: National Climatic Data Center (NCDC).


Figure 2. Historical precipitation ranking for the U.S. for March 2013. Although only two states had a top-ten driest March--Wyoming and Louisiana--just eight states were wetter than average, making March 2013 the 5th driest March on record for the U.S. as a whole. Image credit: National Climatic Data Center (NCDC).

Fifth driest March on record in the U.S.
Although only two states had a top-ten driest March in 2013--Wyoming and Louisiana--just eight states were wetter than average, making March 2013 the 5th driest March on record for the U.S. as a whole. Thanks to three major winter storms that crossed the Great Plains during the first half of April, there should be a notable improvement in drought conditions over much of the core U.S. drought region when Thursday's Drought Monitor report is issued, though. The most recent report from April 9 showed a big reduction of the area in the worst drought category, "Exceptional", from 5% to 3%, during the first week of April. About 51% of the U.S. is still in moderate or greater drought. According to data from the Rutgers Global Snow Lab, the March snow cover extent for the contiguous U.S. was the 10th largest March snow cover extent in the 47-year period of record. However, snowpack, an important water resource in the West, was below-normal in the Sierra Nevada Mountains as well as the Central and Southern Rockies.


Figure 3. Severe weather outlook for Wednesday, April 17, calls for a "Moderate Risk" of severe weather over much of Oklahoma, and portions of surrounding states. The main threat appears to be large hail, but there may also be a few strong EF-2 and EF-3 tornadoes. You can follow today's severe weather outbreak from our Severe Weather page, and wunderblogger Lee Grenci has a detailed post on today's severe weather threat.

Jeff Masters

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Quoting indianrivguy:


Does it smell like hemp? :)
I love the smell of hemp in the morning
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Quoting muddertracker:


Whoever is found guilty of this crime deserves this and worse!
Got that right
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See also increasing tornado threat tomorrow—widespread, though not too high in any one area:
AL northwest - 3 to 4
AR - 3 to 4
IL central, northeast - 5
IL south - 4
IL west-central - 3
IN west - 5
IN east - 4
KY west half - 3 to 4
LA west, central - 3
MI south half - 4
MI northern lower peninsula - 3
MO northeast, central, south - 3 to 4
MS north - 4
MS west-central - 3
OH west - 3
OK east - 3
TN west half - 4
TX from I-35 east - 3
WI extreme southeast - 3 to 4
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Quoting RitaEvac:
Smoke is pouring in from Mexico and over the BOC, streaming right into TX, very hazy here.


Does it smell like hemp? :)
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Did anyone notice that Greg Forbes upped TorCon to 7 in OK? Probabilities raised in most other areas too:
GA extreme north - less than 2
IL south - 4
IL north - 1
IN west-central, northwest - 1 to 2
IN south - 2
KS south-central, east-central - 3
KS southeast - 4
KY central - 2
MO south half - 5
MO north half - 3 to 4
NC west - 2
OK central, southwest - 7
OK northwest (excluding panhandle) - 5
OK northeast - 6

SC extreme north - less than 2
TN east - 2
TX east panhandle - 3 to 4
TX northwest near Abilene, Wichita Falls - 5
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I'm expecting to be upgraded to a flood warning anytime now...
Member Since: July 2, 2011 Posts: 0 Comments: 1183
30 minutes, 3 more degrees, now 76 here, 80 to NW in Spfld, 81 to SW in StL. Dew Pt up to 70, but RH down to 83%. Edit: Clouds or out flow must be getting to Spfld - dropped to 76.5
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Quoting PedleyCA:


That is just nasty, Northern Canada is sure toasty, not good.....

Yep. Up around 10 C above average for a whole week. That's 18 F above avg. for those following at home. The month-to-date (17 days) is worse.

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Quoting bappit:

Can't pass this up. Past seven days temperature anomalies.

that pic sez a lot about the weather for the next ten days, and a lot could happen..This sez a bit about today..
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A watch in portions of Illinois and Indiana is likely to be issued within the next hour.

Mesoscale discussion #496
Member Since: March 16, 2012 Posts: 127 Comments: 7972
New SPC outlook has added 45% wind probabilities.

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Quoting RitaEvac:
Smoke is pouring in from Mexico and over the BOC, streaming right into TX, very hazy here.


Yep... Looking forward to Cold front tomorrow to clear this nasty air out of here.
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The structure of the supercell heading in the vicinity of Carnegie is improving. Heads up around there. TVN has a chaser on that cell with fairly low base.

Member Since: July 15, 2006 Posts: 17 Comments: 10284
Quoting PalmBeachWeather:
Maybe we could tie him to my Jeep Wrangler and drag him down to a different venue... I think my friends might have suggestions...Just a thought


Whoever is found guilty of this crime deserves this and worse!
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Quoting MississippiWx:
MDR warming has resumed and in a big way. Rather large jump in just a day's time.





For analysis purposes, I should point out that jumps between two adjacent days such as that one are almost always not actually 24-hour jumps. They are usually a result of some satellite data being unavailable (e.g. obscured by clouds) for a few days, and then suddenly updating and causing an additional contribution to the anomaly, which results in apparent jumps like that one.
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The Weather Channel ‏@weatherchannel 26m
#TornadoHunt crew is en route to intercept 1 of the 2 severe-warned supercells over SW Oklahoma.
Member Since: April 23, 2011 Posts: 104 Comments: 14873
Quoting TomTaylor:
Levi, if you're on here,

TCHP Anomalies are another possibility for you to explore. Current anomaly, anomaly delta, anomaly time series...lots of options, up to you.


Believe me I know. I'll get to it....eventually. I've been trying to get some things done that Dr. Maue doesn't already offer, so that you guys can have a well-rounded product suite.
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Quoting bappit:

Can't pass this up. Past seven days temperature anomalies.



That is just nasty, Northern Canada is sure toasty, not good.....
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Quoting muddertracker:


Mass. does NOT have the death penalty. Hopefully this is tried as a federal case. (Ala McVeigh?) Not sure.
Maybe we could tie him to my Jeep Wrangler and drag him down to a different venue... I think my friends might have suggestions...Just a thought
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Quoting TomTaylor:

Can't pass this up. Past seven days temperature anomalies.

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Slight rotation beginning with the storm north of Snyder in SW Oklahoma. This one has solid potential as it has little interference from other cells and moves deeper into the heart of the better environment for supercells. I'd pay attention if I were in Carnegie.

Member Since: July 15, 2006 Posts: 17 Comments: 10284
Bring on the rain!

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
332 PM AST WED APR 17 2013

.SYNOPSIS...AT UPPER LEVELS...CYCLONIC FLOW AND A JET WILL
CONTINUE OVER THE LOCAL AREA THROUGH SATURDAY. ANOTHER TROUGH
APPROACHING THE DOMINICAN REPUBLIC WILL CAUSE THE FLOW TO BECOME
WEST SOUTHWEST AND INCREASE TO 75 KNOTS ON FRIDAY. THE TROUGH WILL
PASS ON SUNDAY WITH ANOTHER JET FROM THE NORTHWEST PASSING OVER
THE AREA ON MONDAY WITH SUBSIDENCE INDUCING DRYING AT LOWER LEVELS.
ANOTHER RIDGE WILL BUILD OVER THE AREA NEXT WEEK.

AT MID LEVELS...A TROUGH WILL EXTEND FROM THE EAST OVER OR VERY
NEAR THE LOCAL AREA THROUGH MONDAY MORNING. HIGH PRESSURE WILL
BUILD OVER THE WESTERN ATLANTIC TONIGHT AND THURSDAY AND REACH
PEAK INTENSITY ON SATURDAY WHICH WILL FINALLY CLEAR THE TROUGH
OVER THE AREA EARLY NEXT WEEK.

AT LOWER LEVELS...A PLUME OF MOISTURE CONTINUES TO EXTEND INTO THE
LOCAL ATLANTIC WATERS FROM JUST EAST OF THE LEEWARD ISLANDS.
MOISTURE WILL GRADUALLY INCREASE OVER THE EASTERN CARIBBEAN AND
THEN SPREAD INTO PUERTO RICO AND THE U.S. VIRGIN ISLANDS TONIGHT
THROUGH SATURDAY. THE EASTERLY WINDS WINDS GAIN A NORTHERLY
COMPONENT OVER THE WEEKEND AND MOISTURE BECOMES MORE BANDED
YIELDING DISTINCT BANDS OF NO RAIN AND SCATTERED SHOWERS MONDAY.
MOISTURE SLOWLY RETURNS DURING THE REST OF THE WEEK.


&&

.DISCUSSION...RELATIVELY STRONG TRADE WIND FLOW GENERATED BAND OF
INTENSE SHOWERS OVER PUERTO RICO AND A FEW STREAMERS MOVED OVER
THE NORTHERN U.S. VIRGIN ISLANDS AS WELL. RAIN GAGES SO FAR HAVE
SHOWN THE HIGHEST AMOUNT FALLING IN RIO GRANDE DE ANASCO...WHILE
RADAR SHOWED THE HIGHEST AMOUNT FALLING IN CENTRAL GUAYNABO WHERE
NO RAIN GAGES COULD CONFIRM. AS OF 3 PM AST...THE NORTH COAST FROM
VEGA BAJA TO AGUADILLA WAS DRY AS WAS THE CORRIDOR FROM ARECIBO
THROUGH MOROVIS TO SALINAS. EAST TO EAST NORTHEAST FLOW WILL
CONTINUE IN THE LAYER UP TO 700 MB AND WILL BRING INCREASINGLY
SHOWERY ACTIVITY. AT THIS TIME IT APPEARS THAT THE BEST MOISTURE
AND DYNAMICS WILL OCCUR OF FRIDAY BUT MOISTURE WILL CONTINUE TO BE
SUFFICIENT FOR WET WEATHER THROUGH SUNDAY MORNING ACCORDING TO THE
GFS AND THIS SOLUTION HAS BEEN BOTH REASONABLE AND PERSISTENT. ON
MONDAY MID LAYERS DRY ABRUPTLY AND MOISTURE IN THE FLOW OUT OF THE
CENTRAL ATLANTIC WILL BE LIMITED. THIS WILL LIMIT SHOWERS OVER THE
AREA TO JUST A FEW LOCALES IN SOUTHWEST INTERIOR PUERTO RICO.

&&

.AVIATION...
MOUNTAIN OBSCURATIONS ARE LIKELY THIS AFTERNOON AND
EVENING. SHRA AND ISOLD TSRA ACTIVITY EXPECTED TO CONTINUE AT LEAST
UNTIL 18/00Z FOR THE AREAS IN AND AROUND TJMZ AND TJPS. PASSING SHRA
WILL AFFECT TIST/TISX...TNCM/TKPK AND TJSJ OVERNIGHT. WINDS OVERNIGHT
WILL BE MAINLY FROM THE EAST AT AROUND 10 KNOTS OR LESS...GUSTY NEAR
SHOWERS.

&&

.MARINE...SWELL OF 16 SECONDS HAS REACHED 7 FEET AT BUOY 43044 TO
THE NORTH NORTHEAST OF THE AREA...AND WILL TAKE ABOUT 14 HOURS TO
REACH BUOY 41043. NEVERTHELESS EARLY SWELL OF 5 FEET ARE NOW
REACHING BUOY 41043 AND SEAS WILL INCREASE IN THE LOCAL AREA
OVERNIGHT. SMALL CRAFT ADVISORIES WILL BEGIN TO GO UP TONIGHT
STARTING IN ZONE 710 AND BY MIDNIGHT THURSDAY NIGHT ALL OF THE
ATLANTIC AND CARIBBEAN PASSAGES ARE EXPECTED TO HAVE AREAS OF 7
FOOT SEAS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 86 74 85 / 60 60 50 50
STT 75 85 75 82 / 60 60 40 40
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Quoting LargoFl:
KILL THIS SOB.............BOSTON (AP) --
CNN is reporting that sources tell them that an arrest has been made in the Boston Marathon bombings that killed three people and wounded more than 170 others.
Now they are saying they haven't made an arrest.
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Okla sure needs this rain.
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Smoke is pouring in from Mexico and over the BOC, streaming right into TX, very hazy here.
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My local internet had been down, so wasn't able to track rise, but we're up to 73 w/ 69 dew pt (90%RH)and you could just feel it get sticky from 1 to 2:30. S winds @ 10 w/ 20 gusts and sunshine priming the atmosphere, even stickier than last Wed., and that spawned two tornadoes in StL metro w/ a 101 straight line gust and many 50-60s. We (& StL city) are just east & south of 114 watch area by a county. (Edit: OOps does include City, didn't look like it from box)

Had a total 1.7" in guage yesterday afternoon. 1.1" more overnight, so already 3.5 since Sun. night, needless to say, in flash flood watch.
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Quoting bappit:

Thanks for the link. Found this image. Seems like two areas where warm, humid air is advancing--[or else where it is raining. oops]

Link

Interesting. There were two areas of light rain earlier where the dewpoints were increasing. Everything else was pretty static. Now there is one area where the dewpoint has dropped as much as 15 degrees with a nearby rise in dewpoint. Looks like a downdraft has brought dry air to the surface.

Edit: That's near the severe tstorm warnings in SW Okla.
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Levi, if you're on here,

TCHP Anomalies are another possibility for you to explore. Current anomaly, anomaly delta, anomaly time series...lots of options, up to you.
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Dr. Ryan Maue from WeatherBell has allowed open access to his SST/TCHP page as well as his global temperature anomaly page. If you haven't seen this before, I'd check it out. On the SST/TCHP page you can see current SSTs/TCHP, SST/TCHP anomalies, and SST/TCHP anomaly comparisons to previous years. On the global temperature anomaly page you can find plots of temperature anomalies over North America, Europe and the Globe, as well as time series plots for temperature anomalies.

Current TCHP Anomaly
as an example




Operational forecast model products will require a subscription, however.
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and another watch possible for Texas
Member Since: April 23, 2011 Posts: 104 Comments: 14873
Quoting Ameister12:
Classic looking supercell in SW Oklahoma. Fortunately, it has no evident rotation ATM.



It is just behind the warm front, so unless it attaches onto the front, tornado potential will be pretty much zero as it will be elevated
Member Since: July 18, 2010 Posts: 50 Comments: 1909
Member Since: July 15, 2006 Posts: 178 Comments: 56140
Quoting wxgeek723:


OH MY GOD REALLY THAT'S NEVER HAPPENED BEFORE


I know right???

I don't even know why you come up with that in the first place
Member Since: April 23, 2011 Posts: 104 Comments: 14873
Quoting trHUrrIXC5MMX:
TORNADO WATCH JUST ISSUED FOR OKLAHOMA CITY





OH MY GOD REALLY THAT'S NEVER HAPPENED BEFORE
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.
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Classic looking supercell in SW Oklahoma. Fortunately, it has no evident rotation ATM.

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Now I see why flooding will be an issue. I'm going to get this whole line of heavy rain non-stop. The rain started just a little while ago here and will only get worse and persist from here on out.

Member Since: July 2, 2011 Posts: 0 Comments: 1183
Quoting Doppler22:
Today is going to get interesting soon... also looks like tomorrow will be well


Maybe, but there have been a lot of 'busts', lately.
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Today is going to get interesting soon... also looks like tomorrow will be well
Storms near Vernon, TX and Altus, OK need to be watched
Member Since: February 13, 2012 Posts: 11 Comments: 3880
56 PedleyCA: "Ever walk into a room with some purpose in mind, only to completely forget what that purpose was? Turns out, doors themselves are to blame for these strange memory lapses."

"In the final stage of the test, he led subjects through several doorways and returned them to where they began to see if the memories were associated with that room, but their memories showed no signs of improvement, suggesting that it was the doors' fault."
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Latest SPC alerts... 5 as of now

MO, OK, NE Tornado watches (3)
TN, IA-IL Storm watches (2)

Member Since: April 23, 2011 Posts: 104 Comments: 14873
Quoting MississippiWx:
MDR warming has resumed and in a big way. Rather large jump in just a day's time.





Looks like the breeding ground will be open for business. CapeVerde season could be strong.
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MDR warming has resumed and in a big way. Rather large jump in just a day's time.



Member Since: July 15, 2006 Posts: 17 Comments: 10284
85 in FLL... now this is spring!
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H7N9 bird flu update:
Excellent article from Nature here:

Link

Extract

The H7N9 avian flu virus greatly expanded its geographical range over the weekend, with two new human cases reported in Beijing in the north of China, and another two in Henan province in the centre. Up until now, the virus had been restricted to Shanghai and neighbouring regions on the Eastern seaboard. Experts worry that this new development may be the start of an expansion that may see H7N9 quickly fan out across large areas of China, and beyond.

"I think we need to be very, very concerned" about the latest developments, says Jeremy Farrar, director of the Oxford University Clinical Research Unit in Ho Chi Minh City, Vietnam
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Quoting SFLWeatherman:
Boston Marathon bombing arrest: Suspect taken into custody, CNN says

Link


Meh, don't really care about the bombing anyways. But I dont think they have the right guy.
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194. MTWX
Quoting trHUrrIXC5MMX:


the prime area is around Oklahoma


I agree, and I think SPC does too. Just found the differences in the watches to be interesting...
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New Tornado watch 117

Member Since: April 23, 2011 Posts: 104 Comments: 14873
Quoting MTWX:


Just messing with ya Max... LOL! You have gotten quite good at this over the years, so I got to pick at you mess up... ;)


nice one..
and elusive too!

check my blog for more info if you want...
Member Since: April 23, 2011 Posts: 104 Comments: 14873
Quoting aspectre:
106 weathermanwannabe: For the Florida Panhandle Bloggers........Is it raining in your parts?

dDepens. (Did anyone else initially misread it as pants?)


depends!!!! LOL!!!
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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