Aviation Weather Forecasts

Products for Aviation Hazards

100

What are the criteria for issuance of a SIGMET (WS)?

A SIGMET (WS) may be issued when any of the following conditions occur or is expected to occur in an area affecting at least 3,000 sq. miles or an area deemed to have a significant effect on the safety of aircraft operations: SEV TURB, SEV ICE, WDSPR DS, WDSPR SS, VA (volcanic ash), TC (tropical cyclone).

200

SIGMETS (WS)s have a valid period not to exceed ____ hours.

SIGMETS (WS)s have a valid period not to exceed 4 hours?

300

What are the criteria for issuance of a Convective SIGMET (WST), and what is classified as a Severe Tstorm?

A Convective SIGMET (WST) may be issued when any of the following occurs and/or is forecast to occur: Severe Tstomrs and embedded Tstorms for more than 30 minutes of the valid period, Lines of Tstrorms, An area of active Tstorms affecting at least 3000 sq. miles. A Tstorm is classified as severe when it is accompanied by tornadoes, hail 3/4 inch or greater, or wind gust of 50 kts or greater.

400

What are the criteria for issuance of an AIRMET (WA)?

An AIRMET (WA) may be issued when any of the following weather phenomena are occurring or expected to occur over an area of at least 3,000 sq. miles: Sustained surface wind greater than 30 knots (STG SFC WND), ceiling less than 1,000 feet (IFR, CIG BLW010) or (IFR, VIS BLW 3 SM BR), widespread mountain obscuration (MTN OBSCN), moderate turbulence (MOD TURB), moderate icing (MOD ICE), and non-convective LLWS potential (LLWS POTENTIAL).

500

What is the valid period for an AIRMET (WA), and what are the 3 types of AIRMETs issued?

AIRMETs are issued for conditions occurring or expected to develop within the 6 hour valid period. AIRMET series consist of Sierra (IFR and MTN OBSCN), Tango (MOD TURB, STG SFC WND, and LLWS), Zulu (MOD ICE).

FA - Area Forecasts

100

Area Forecasts (FA) forecast VMC clouds and general WX over an area the size of several states and are issued ___ times per day.

Area Forecasts (FA) forecast VMC clouds and general WX over an area the size of several states and are issued 3 times per day.

200

What are the 4 sections of an FA and their valid periods?

The 4 sections of an FA are: Communications and product header, Precautionary statements, Synopsis (18 hrs), VFR clouds and weather (12 hrs with a 6 hr Outlook).

300

TRUE or FALSE? All height in an FA are referenced to MSL except when prefaced by AGL, CIG, or CEILING. Tops are always referenced to MSL>

TRUE: All height in an FA are referenced to MSL except when prefaced by AGL, CIG, or CEILING. Tops are always referenced to MSL.

400

Refer to figure 1A: Interpret the synopsis section of the FA.

Synopsis 18Z… cold front line from 30 NM north of PQI, 40 NM east of MPV and ALB, and 20 NM north of JHW. Stationary front line... Stationary front line… Trough line… continuing southward. High in western NC. 12Z… stationary front from low near FWA along line... Cold front line... Cold front from low near line... continuing south-westward. High near ODF.

500

What graphical weather product provides a depiction of the same information contained in the synopsis section of an FA?

Prognostic Charts - forecast of pressure systems, fronts, and precip.

TAF - Terminal Aerodrome Forecasts

100

A TAF is a concise statement of expected meteorological conditions significant to aviation for a specified time period within ___ SM of the center of the airport's runway complex (terminal).

A TAF is a concise statement of expected meteorological conditions significant to aviation for a specified time period within 5 SM of the center of the airport's runway complex (terminal).

200

Scheduled TAFs are issued __ times per day, and valid for up to __ hours.

Scheduled TAFs are issued 4 times per day, and valid for up to 30 hours.

300

When is TEMPO used in a TAF?

TEMPO is used to indicate temporary fluctuations to forecast meteorological conditions which are expected to: Have a high percentage (>50%) probability of occurrence, last for one hour or less in each instance, and cover less than half the period.

400

Refer to figure 2: Interpret the TAF.

All the forecast elements in the TEMPO group are expected to be different than the prevailing conditions. The TEMPO group is valid on the 17th from 1500 UTC to 1700 UTC.

500

Refer to figure 3_page 1: Interpret the TAF.

Refer to figure 3_page 2 for answer.

FB - Winds and Temps Aloft Forecast

100

The NWS produces scheduled Wind and Temp. Aloft Forecasts (FB) __ times daily.

The NWS produces scheduled Wind and Temp. Aloft Forecasts (FB) 4 times daily.

200

TRUE or FALSE: Wind direction is referenced to Magnetic North.

FALSE. Wind direction is referenced to TRUE NORTH.

300

Refer to figure 1: What direction and velocity is shown in the wind symbol?

Wind From 270 degrees at 75 knots.

400

Interpret the forecast wind example: 9900+10

Wind light and variable, temperature +10 degrees.

500

Interpret the forecast wind example: 7735-07

The wind direction is from 270 degrees (i.e. west), the wind speed is 135 knots and the temperature is minus 7 degrees Celsius.

Forecast Charts

100

_________ provide a forecast of surface pressure systems, fronts and precipitation for a 2-day period and are issued 4 times/day.

Surface Prognostic (Prog) Charts provide a forecast of surface pressure systems, fronts and precipitation for a 2-day period and are issued 4 times/day.

200

________ provide a forecast of aviation weather hazards primarily intended to be used as guidance products for pre-flight briefings. Each chart is a "snapshot" of weather expected at the specified valid time.

Low-Level Significant Weather (SIGWX) Charts provide a forecast of aviation weather hazards primarily intended to be used as guidance products for pre-flight briefings. Each chart is a "snapshot" of weather expected at the specified valid time.

300

Refer to figure 4_page 1: Interpret the Surface Prog chart for the area in the central US.

Precipitation with 30-50% coverage, moderate snow and light snow showers. A trough extending north-east ward. A warm front moving eastward through MN and OH.

400

Refer to figure 4_page 2: Interpret the SIG WX Prog chart for the area in the central US.

MVFR conditions covering most of the region. IFR conditions covering several states. Areas of moderate turbulence from FL180 to FL240 and from the surface to 8000'. Freezing levels depicted at the surface and varying between 8000' and 4000'

500

Refer to figure 4_page 3: Interpret the High-Level SIGWX Chart Jet Stream symbol.

Forecast max speed of 100 knots at FL310 at one location and 120 knots at FL290 at another location. At the latter location, the base of the 80 knot wind field is FL210, and the top of the 80 knot wind field is FL340.