Lab6

Name: Insert name here Lab 6: Surface Weather Map Analysis Objective: This lab is designed to introduce students to the various coding of time and meteorological variables associated with synoptic weather maps. A detailed analysis of surface weather conditions along with locations of national weather service forecast offices is presented. Materials needed: Pencil, Calculator, Textbook, and US Map Part 1: Time Zone Analysis To correctly use the many available weather maps it’s important to understand the time factors involved. The time given on a synoptic analysis map or surface observation is the time the observation took place. Because at any given moment different places on Earth have different times, a specific time standard had to be established to assure continuity. For example, a surface weather map header may display the time and date as: Analysis for 18Z 24 SEP 06 Valid SUN 09/24/2006 18UTC Both these descriptions are referring to the same time and date. The time is expressed in military time, so the 18Z is 6 hours past noon, or 6:00PM. The "Z” stands for Zulu, which is a communications code word. It represents an arbitrarily chosen value for time. This standard is the time at the prime meridian (zero degrees longitude), the Greenwich meridian. Therefore, Zulu means Greenwich Mean Time (GMT), also known as Universal Coordinated Time (UTC). All of these expressions are referenced from Greenwich, so the time given on a particular chart must be converted to one’s own time. The following table provide the necessary conversions factors. Notice the additional factor for daylight saving time. Time Zone Atlanti c Easter n (EST) Centra l (CST) Mountai n (MST) Pacifi c (PST) Yuko n Alaska n Berin g Time Differenc e from GMT* -4 -5 -6 -7 -8 -9 -10 -11 1

*Note: Subtract one less hour if daylight saving time is currently in effect. Thus the 18Z (1800 UTC) time to a person in the central standard time of the United States would mean 18 – 6 = 1200 hours in military time, which is equivalent to 12:00PM or noon. However, if daylight savings time is in effect, one hour less should be subtracted and 18Z would mean 18 – 5 = 1300 hours or 1:00PM local time Use the time conversion table on the previous page and convert the following times as directed. A. 0000Z to Central standard time 6PM B. 0600 Z to Mountain standard time 11PM C. 12Z to Central daylight time 7AM D. 16Z to Pacific standard time 8AM E. 0300 GMT to Eastern daylight time 11PM F. 2100Z to Mountain daylight time 3PM G. 1230Z to Central daylight time 7:30AM H. 1040Z to Central standard time. 4 :40AM 2. Use the time conversion table on the previous page and convert the following standard times to GMT. A. 10:45 AM CST to GMT 1645 Z B. 9:30 PM EST to GMT 0230 Z C. 12:10 PM CST to GMT 1810 Z D. 3:00 AM PST to GMT 1100 Z 3. Use the time conversion table on the previous page and convert the following daylight times to GMT. A. 12:43 AM CDT to GMT 0543 Z 2

Denver, CO DEN Detroit, MI DT W Raleigh, NC RDU Melbourne, FL ML B Grand Junction, CO GJT Grand Rapids, MI GRR Wilmington, NC ILM Miami, FL MI A Pueblo, CO PUB Marquette, MI MQ T Cincinnati, OH LU K Tallahassee, FL TLH Chicago, IL ORD Duluth, MN DLH Cleveland, OH CL E Tampa, FL TP A Springfield, IL SPI Minneapolis, MN MS P Philadelphia, PA PHI Lake Charles, LA LCH Des Moines, IA DS M Kansas City, MO MC I Pittsburg, PA PIT New Orleans, LA MS Y Davenport, IA DVN Springfield, MO SGF Charleston, SC CHS Shreveport, LA SHV Dodge City, KS DDC St. Louis, MO STL Columbia, SC CA E Oklahoma City, OK OK C Goodland, KS GLD Caribou, ME CAR Greenville, SC GSP Tulsa, OK TU L Topeka, KS TOP Portland, ME PW M Birmingham, AL BH M Knoxville, TN DK X Wichita, KS ICT Albany, NY ALB Huntsville, AL HS V Memphis, TN MEJ Lexington, KY LEX Binghamton, NY BG M Mobile, AL MO B Nashville, TN BN A Louisville, KY LOU Buffalo, NY BU F Jacksonville, FL JA X Boise, ID BOI Paducah, KY PAH New York City, NY NY C Key West, FL EY W Pocatello, ID PIH Amarillo, TX AM A Lubbock, TX LBB Flagstaff, AZ FLG Hastings, NE HSI Brownsville, TX BRO Green Bay, WI GR B Phoenix, AZ PH X North Platte, NE LB F Dallas, TX DE W La Crosse, WI LSE Tucson, AZ TUS Omaha, NE OM A 4

Wind is from SW at 15 knots Part 3: Synoptic Scale Surface Weather Maps National Weather Service stations report data every hour on synoptic scale maps. At times of significant weather, reports are often more frequent. Synoptic scale maps are concerned with weather phenomena on a large scale where as meso-scale and micro-scale are concerned with increasing smaller scale weather phenomena. Weather conditions at locations around the country are observed and recorded on surface weather maps. The data plotted on these maps are then analyzed for interpretation of weather patterns. In order to use and understand surface weather maps, it is necessary to become familiar with the coding system used on such maps. The information collected at each observation point is concisely given a coding scheme called a station model . In this exercise you will learn to read part of the information given by a station model and to draw a station model from given weather data. The following figure explains how to decode a typical surface station model. El Paso, TX ELP Milwaukee, WI MK E Seattle, WA SE A Rapid City, SD RA P Houston, TX HOU Rockford, IL RF D Spokane, WA GEG Sioux Falls, SD SFD 5

Wind Direction: The wind direction is listed as the symbol denoting the direction from which the wind is blowing. The example shows a wind direction blowing from the northwest. Wind Speed: The wind speed is specified as feathers, half- feathers, and / or flags on the wind direction bar. Each full feather represents 10 knots (12 mph), and each half-feather represents 5 knots (6 mph), and each flag represents 50 knots (55-60 mph). The example shows a wind speed of approximately 15 knots (15-20 mph). For wind speed determination the following symbols can be represented as: 7

Amount of Precipitation: The amount of liquid precipitation over the last 6 hours is provided in hundredths of an inch, and is always located at the bottom right of the station circle. The example omits the decimal point. The example shows that 0.22 inches of precipitation fell within the last 6 hours. Present Weather: The present weather is listed as a symbol and is always located at the left center of the station circle. The example shows two dots representing light rain if presently falling. There are over 100 weather symbols and some of the common ones we will utilize in this course include the following: To indicate the intensity of the precipitation, the rain, snow, and drizzle symbols may be duplicated to indicate heavier or more continuous rain. For example, the following symbols would represent: Heavy Rain Moderate Rain Light to Moderate Rain Light Rain 8

2. 3. Temperature ( 0 F) 75 Dew point ( 0 F) 71 Pressure (mb) 998.2 Press. Change (mb) -3 Precipitation (in.) 0.13 Pressure Tendency Steady then falling Wind Speed (mph) 25 Wind Direction SE Cloud Cover Overcast Present Weather Thunderstorm Temperature ( 0 F) 28 Dew point ( 0 F) 25 Pressure (mb) 1000.3 Press. Change (mb) -1.1 Precipitation (in.) 0 Pressure Tendency Falling Wind Speed (mph) 10 Wind Direction N Cloud Cover Mostly cloudy Present Weather Light snow 10

Temperature ( 0 F) 45 Dew point ( 0 F) 44 Pressure (mb) 1019.7 Press. Change (mb) 2 Precipitation (in.) 0 Pressure Tendency Rising Wind Speed (mph) 5 Wind Direction Se Cloud Cover Obscured Present Weather Fog 11

Surface Weather Map 20Z 25 NOV 96 13

Answer the following questions associated with the National Weather Service's current conditions map as shown in the above map. When necessary use an atlas provided by the instructor to determine city names. 1. What local time (Central Time Zone) were the observations taken? 2 PM 2. What is the date of the observed map? November 25th 1996 3. What is the observed lowest pressure on the map? 991.2 mb 4. What's the name of the city, state recording the lowest pressure? Peoria IL , 5. What's the observed highest pressure on the map? 1026.3 MB 6. What's the name of the city, state recording the highest pressure? Rapid City, SD , 7. Name a city, state which is currently experiencing heavy snow? Madison, WI , . 8. What is the coldest observed temperature on the map? 1 F 9. Fully decode Madison, Wisconsin's weather and place your data on the table below. 10. Fully decode Nashville, Tennessee’s weather and place your data on the table below. Temperature ( 0 F) 26 Dew point ( 0 F) 24 Pressure (mb) 1001.3 Press. Change (mb) NA Precipitation (in.) NA Pressure Tendency NA Wind Speed (mph) 23 Wind Direction NE Cloud Cover Obscured Present Weather Heavy snow 14

, Clarksburg, WV. 65 and 18 are the differences which is 47 F 14. Why do you think the city in the previous question is so dry? When the altitude increases the air becomes drier 15. What’s the strongest wind speeds on the map, and what’s the direction of these winds? 30 Knots from the northwest in Nebraska 16. What’s the predominant wind direction for locations in Iowa? North 17. What’s the predominant wind direction for locations in Indiana? South 18. Some of the locations are reporting obscured skies? What does this mean, and what is causing the skies to be obscured at these particular locations? Click here to enter text. Part 4: Surface Metar Reports Surface weather reports are routinely reported on an hourly basis unless something significant is occurring. The reports are usually placed into a coded format called a Metar. A Metar for Little Rock, Arkansas may look like the following: KLIT 200953Z 00000KT 4SM -RA BR OVC030 07/05 A3013 RMK AO2 SLP205 16

17

Use the web site: https://www.weather.gov/media/wrh/mesowest/metar_decode_key.pdf for an in-depth analysis of all the possible codes and remarks that can exist with a metar report. The following represents a report from a metar. The decoded data is provided below. KRFD 262354Z 20004KT 10SM FEW250 17/04 A2985 RMK AO2 SLP111 T01670039 10217 20167 Station Rockford, IL Date 26 th of the month Time 2354 Z (6:54 PM CDT) Wind Direction 200 degrees (SW) Wind Speed 4 knots Visibility 10 miles Clouds Few clouds at 25,000 feet Temperature ( 0 C) 17 0 C Dew point ( 0 C) 4 0 C Altimeter 29.85” Sea Level Pressure 1011.1 mb Precise Temperature 16.7 0 C Precise Dew point 3.9 0 C 6 hour Max. Temp 21.7 0 C 6 Hour Min. Temp 16.7 0 C Remarks None 19

1. Decode the following 2 Metars by placing the current weather conditions in the table. Use the table above for assistance in decoding. For time, make sure you provide the local time of the observation with the Zulu time. KORD 220351Z 16007KT 10SM OVC090 16/06 A2991 RMK AO2 SLP127 T01610061 KSPI 061552Z 00000KT 10SM CLR 26/14 A3013 RMK AO2 SLP199 T02560139 Station Springfield IL Date 6 th Time 10:52 AM 9:52 am Wind Direction calm Wind Speed Calm Visibility 10 miles Clouds None Temperature ( 0 C) 26 C Dew point ( 0 C) 14 C Altimeter 20